Want to make this Split and Slide Effect achieved in After Effects in the VSE

Splitting screens:

The method I've used here is using the same principle for both.  A 2D plane for each video, one laid just above the other and the camera looking straight down.

Note:  Both are rendered using OpenGL, not Blender's internal render.

With the split screen an 'inviso mask' face was added to the lower edge of the white line. (thin rectangular plane laid just above the  video planes)  The line was simply rotated.

(inviso mask - plane with transparency set to 0.008)

In the torn or jaggy edge version, a single plane was used and textured with it's video.  A jagged edge (vertices) was cut into that using the knife function.  That was then duplicated (SHIFT-D) and dropped a little under the first

At the opening frame, only the top plane and video can be seen until reaching the frame where shape keys INSTANTANEOUSLY fold the respective outer edges of each plane downward and underneath. (hinged at the jagged edge)

In this example the left side of the top plane, and right side of the lower plane are folded down at the exact same frame that we start to rotate (tear) both planes out from the bottom center. (origin point set to the cursor which is already set to bottom center)

Twisting the planes in the Z axis on the way down can enhance the effect.

Underneath both planes a 3rd can be added as shown here textured with our favorite movie studio pattern.

Both Blend files are attached and compressed. VE5 (the 2nd) the straight out split screen, VE4 (1st) the torn screen.

If as you mentioned, you're still needing video footage as to how it was done that can be organised.  (hasn't been done yet)

The Blender files: (You'll need to substitute the original videos with your own)

Note:  Rendering used OpenGL, not Blender's internal render.

Thanks also to @3pointedit.  That could be another solution for you to try.


why does baked procedural texture look pixelated

There will always be a loss in quality when baking a shader to an image. The higher resolution the blank image you are baking to is, the better the resolution the texture appears. Try making the blank target image higher resolution.


Importing shapefiles with other CRS other than Web Mercator and WGS84_latlon

I've checked your shp and It seems ok. The GIS importation has any problem if you do this:
Check the shp first to be sure about the projection:

To add some elements of reference to this piece, I've created a point layer to get some perspective:

Then I've imported the point into the scene just using web mercator (dont worry for the moment as the projection of these will be ok with your layer...)
CRITICAL PART: Now, I've imported your shp using your CRS...BUT...when you specify other than Web mercator, I mean, a defined CRS (7856 in this case), you have to remove the Scene georeferencing...

...to see something like this:

Doing so Blender has no problem to locate all the elements within the scene. As you can see, they are correctly positioned to each other. Here is just a view of the points and your line (shp):


What is the reason for partially allowing visibility control of linked objects in the outliner?

When you link objects the linked object reflects the object in another .blend file. It wouldn't make sense for user to seem to be able to make changes to it.

When you link groups you are not really linking the objects themselves, but a new instance of the collection of objects. Its the same as when operating within the same .blend: new instance of object can be manipulated without affecting the original copies as long as you don't manipulate the data ie. mesh itself for mesh objects.


can't fix mesh texture does anyone have a sloution?

What you need to do is select the top faces, select one to make it active, unwrap with the Follow Active Quads option:

Then move the UVs so that the bricks match each other:


Glass cup + Water not rendering correctly, weird lines

Lines in transparent materials are a telltale sign of intersections with other objects. This was no exception.
To verify that there were intersections between the liquid and cup objects, I took these steps to generate a mesh that resembles the intersections:

Tab out of edit mode. This only works in object mode.
Select the liquid.
Hit the "Modifier Properties" tab of the properties window.
Create a new Boolean modifier (it's under the Generate group) with the following properties.

Operation: Difference
Object: Cup
Overlap Threshold: 0

Below is the screenshot of the results:

Yep, the cup and liquid definitely intersect. And notice how those lines match the lines in the render.
One way to fix the problem is by shrinking the liquid in the x and y axes. Here's how I did it:

Remove the Boolean modifier (that was just to see the intersections)
Select the liquid and only the liquid.
Tab into edit mode
Hit a to select all vertices
Hit s to scale them
Hit shift and z to lock the transformation in the Z axis.
Enter 0.99.
Tab out of edit mode.

Now the cup should look like this:

At first glance, it doesn't look like anything changed. But when you render the scene...

...no more lines!
One other thing to note is that the cup has some duplicate vertices. Make sure to use the "Merge by Distance" tool occasionally to clean those up.


What you are seeing is Blender's smooth shading view trying to smooth out the appearance of the faces. Whenever you add new faces, you give Blender more faces to try and shade smooth. Before adding the face, the original face was an edge. Now you are telling Blender that it is actually a corner, and thus the shading is updated. Now, the other reason for how the shading looks is that the original face is an ngon, so it has more than 4 faces. Ngons are much more prone to shading issues, as they have to be triangulated before rendering, and this can lead to unexpected behavior. Especially in this case, you should try to avoid them. Look into trying to clean that up and make your topology better. There are plenty of resources out there for that, both on this site and elsewhere.


Is it possible to assign a hotkey on the checkbox

Yes it's possible. Go to your User Preferences, Section Input, and navigate to 3D View, Object Mode:

Then, add a hotkey for Object Mode only, and use these settings:

Operator Name: wm.context_toggle
Hotkey: F4
Context Attribute: object.show_wire

This Operator allows you to toggle many boolean properties if they are accessible reliably via Python. You can test it by going to a Python console and typing in:

bpy.ops.wm.context_toggle(data_path='object.show_wire')

The object.show_wire part is referring to the Active Object, searching for a property called show_wire on it. so if you try this instead, the X-Ray Property will be toggled instead:

bpy.ops.wm.context_toggle(data_path='object.show_x_ray')

If you want to have the operator working for any mode in the 3D View, add the shortcut under the 3D View Global section.


I took a look at your blend and it is because when you added the beard (Particle system) you told blender to hide the model.

Just check this box.


Create the tape (from a plane) approximating the shape of the battery and wire.
Go into sideview and extrude the plane. (the more accurate this is done the better will be the result)

Subdivide it, to get higher resolution (the more verticies it has the better will be the result). You can use Catmull-Clark or Simple both work.

Duplicate the object you want to get wrapped (select objects and press ctr + d,the location,rotation and scale has to be the same as the original)

Join the duplicated objects to one Mesh and hide the original objects (select the objects you want to hide and press h, select the objects you want to join and press ctrl+j)

Select the tape and add the shrinkwrap modifier

select the object you want to wrap around as target (battery and wire)
set the mode to Project
set the axis to x and z (this depends on the orientation of your scene, ether x and
z or y and z)
check at direction both Positive and Negative

Add a solidify modifier, to add thickness to the tape

Hide (not vieible in viewport and render) the copy and unhide the original objects.
And add smooth shading.

You can increase the subdivision level afterwards to get more or less detail.


Cutting Holes with Boolean Modifier Makes Subdivision Surface Impossible

Invert the order of the modifiers, do the subsurf before the boolean.

Instead of this:

Do this:


Are you making this in 2D or 3D? If 3D, you can use a spot light and position it in the headlight of the car, keyframing it's position. You also wouldn't need to use nodes for that.

If 2D, and you want to have it be casting a yellow tint on the background, then you can make the light a yellow plane and decrease the alpha transparency value.


Mechanical modeling: placing a bar between two ball joints

Something like this:

Place the origin of the cylinder at one end.
Parent the cylinder to the first sphere.  Reset the cylinders origin (Alt+O) to position the end of the cylinder at the first sphere.
Add a Track To constraint (Ctrl+T) to the cylinder with the target as the second sphere.  Adjust the track axes until the cylinder is aligned towards the second sphere.
Apply the visual transformation (Ctrl+A) and delete the Track To constraint.
Scale the cylinder along the local Z axis (S,Z,Z) until it intersects with the second sphere.


Python - Changing scenes' header color gives fever to CPUs

Why so CPU intensive?

Blender will call that function far more often than you think. Prove to yourself by adding a print statement in the function. that will explain the excessive CPU consumption.  It' s a neat idea but this is not the way to implement it. There are no events that fire off upon scene change, else that would be a great idea for an event handler.

One possible approach

I'm hoping this will anger someone else into giving a better answer :)
An alternative is to code a dedicated menu for switching scenes.. something like this.. (use better class names than these )

this gives a menu of scenes in the current blend
lets you pick one
switches color
switches scene

--

import bpy

class SimpleSceneOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "scene.select_and_color"
    bl_label = "Simple Select Scene and Color"

    scene_name = bpy.props.StringProperty()

    def execute(self, context):
        pref = context.user_preferences
        header_colors = [(1.0, 0.7, 0.7),(0.7, 1.0, 0.7),(0.7, 0.7, 1.0)]

        if self.scene_name == 'Editing table':
            col = 0
        elif self.scene_name.startswith("Tag: "):
            col = 1
        else:
            col = 2

        pref.themes[0].info.space.header = header_colors[col]
        context.window.screen.scene = bpy.data.scenes[self.scene_name]
        return {'FINISHED'}

class CustomMenu(bpy.types.Menu):
    bl_label = "Custom Menu"
    bl_idname = "OBJECT_MT_custom_menu"

    def draw(self, context):
        l = self.layout
        col = l.column()
        col.label(text="pick a scene")

        opname = "scene.select_and_color"

        for sc in bpy.data.scenes:
            col.operator(opname, text=sc.name).scene_name = sc.name

def draw_item(self, context):
    layout = self.layout
    layout.menu(CustomMenu.bl_idname)

def register():
    bpy.utils.register_class(SimpleSceneOperator)
    bpy.utils.register_class(CustomMenu)
    bpy.types.INFO_HT_header.append(draw_item)

def unregister():
    bpy.utils.unregister_class(CustomMenu)
    bpy.utils.unregister_class(SimpleSceneOperator)
    bpy.types.INFO_HT_header.remove(draw_item)

if __name__ == "__main__":
    register()

    # The menu can also be called from scripts
    # bpy.ops.wm.call_menu(name=CustomMenu.bl_idname)

could be triggered from 3dview, if you assign a shortcut to it, else the current code adds a menu item to the end of the info header, not ideal but gets the idea across.


GPU Rendering with LuxRender - Where is SLG Path OpenCL option?

SLG has been merged into LuxRender under the name "LuxCore".
It now supports almost every feature of "Classic Lux" and contains many improvements, most notably in the speed department.

So what you will want to use is either "LuxCore Path OpenCL" in your screenshot above, or switch LuxBlend into native LuxCore mode: http://www.luxrender.net/wiki/LuxBlend25_LuxCore

To use GPU rendering in LuxCore mode, go to the render settings panel and switch from CPU to OpenCL:

Note that OpenCL rendering is only available when using the Path or Biased Path engine.


Shortcuts have randomly changed mid-project

The main thing to check is which keymap is active under the keymap settings in the preferences. Try the default ones to see which one fits the one you used previously.
For custom keymaps:
I favour disabling autosave under preferences so you can manually save the preferences & keymaps. If you've customised the keymap, make sure to export it to a different folder as backup so you can always import it again later. Preferences are saved under "Username"/appdata\Roaming\Blender Foundation\Blender


Shrinkwrap to project in the direction of view

The Project directions are in local coordinates rather than global (world) axes. Therefore, to change the direction of the projection you can simply rotate the object such that it faces in the direction you want the projection to be in.

In order for it to always point towards the camera you can simply add a Constraint to Track To the camera.


How do you enable rigid body physics for a given object in Blender 2.8?

This question is related to How do I add a rigidbody to an object with python?.

In 2.8 you need to use collections, so if you want to add rigid body physics to object my_object for scene 'Scene':

bpy.data.scenes['Scene'].rigidbody_world.collection.objects.link(my_object)

and verify outcome with

my_object.rigid_body is not None


Snow fall on grass: Cause emitted particle to stick to hair particle system, ideally unconverted

Unfortunately, the short answer is "no, hair systems only interact with colliders, not other particle systems."

The slightly longer answer is that you might be able to make it LOOK like the particles are interacting with the hair if you set up a collision object that's within the hair. The particles could land on this invisible collision surface. Model the surface of your collision object to have some high-frequency bumps and you might be able to convince your viewer that the particles are landing in the hair.


Can I mask out a string property field that holds a password?

Yes, use the subtype='PASSWORD' for a StringProperty:

bpy.types.Scene.password = bpy.props.StringProperty(subtype='PASSWORD')

You can add it to the Scene tab for a quick test by running:

bpy.types.SCENE_PT_scene.prepend(
    lambda self, context: self.layout.prop(context.scene, "password"))

The property can be read and written like any property, but each character is drawn as an asterix if added to a panel. It is also not shown in tooltip (since 2.70), but it's possible to copy and paste. The main purpose is to hide the password on screen for video recordings, not to protect or encrypt it.


It's a very challenging set of questions. As with any set of questions, the answer depends on contexts. Once you begin looking at the issue of "quality", the solutions are quite clear. The outlines provided below have been with motion picture making since near the advent of film, and continue on to this day in many projects.

It should be noted that you should test your footage in the compositor to see if the result achieves the quality level you need based on your original question. If it doesn't, then the whole following answer may be moot.

  So what is the best way to manage editing of short-movies or longer movies?

What is outlined here is loosely what is described as an offline versus online post production process. The terms offline and online here, do not reference internet connectivity, but rather:

Terms

Offline: Sacrifice quality for performance in a context where performance is deemed more important than quality. This is typically the design context of tools that require real-time interactions, such as the needs of NLEs with editing where timing and beats is more important than precise float precision correctness.
Online: Sacrifice performance for quality in a context where quality is deemed more important than performance. This is typically the design context of tools that require float precision bitwise precise accuracy, such as the needs of compositors and grading software[1].

  Use the VSE and losing quality and flexibility? Use the compositor and losing any sensation of time, trying to align audio strips without even see the waveform? Or Blender is really limited for editing and I should learn an editing software?

The problem here is that your questions actually contain the answer. The TL;DR answer is that you should use both.

Outline

For those unfamiliar with how motion pictures typically are broken down in post production, the following is a high level summary. Animated projects have similar overlaps, but the footage is typically iterations of previsualizations. The path typically looks akin to:

Logging. Log the footage that has been shot.
Editing. Loosely can break down into Assembly, Rough Cut, Fine Cut, Final Cut. At this point the picture is considered "locked", and post production work can commence.
Post Production. Sound etc. forks off here. The outline continues to focus on the picture components. All relevant tasks now have a completed, frame accurate blueprint to work from.
Visual Effects. Work done using compositing tools on a frame by frame basis using the highest quality plausible.
Conforming. Essentially taking all of the various "bits", and assembling them back together into the final shape of the motion picture.
Grading. Grade on the final image frames.

At this point the picture can be reassembled back into the original blueprint's shape, and merged with audio, and encoded to various output encoding needs as required.

Visual Effects

So it would seem that you've managed to edit your piece. The question now becomes, how to achieve this sort of quality baseline with Blender?

Use your VSE edit as a blueprint. Sadly Blender's VSE lacks Edit Decision List support. An Edit Decision List is essentially a text file blueprint that is legible to many different applications. There are a number of formats, but essentially they all communicate the structure of an edit without passing around heavy pixels in files, allowing various softwares to reconstruct elements as required, using the precise edit timing of frames etc. So how to get a useful series of frames out of the VSE if we need to manually accomplish what EDLs are used for?

Make sure your media is using the highest quality inputs. Decoding in Blender from codecs will reduce all codecs, even at higher bit depths, to 8 bits per pixel. This is a limitation of the current system. If you decode outside of Blender using a tool such as FFMPEG, you can generate potentially highest quality sources, and then load those as still images in the VSE.
Keep tight organization on your shots. If you have a short that requires 192 shots, and 17 are visual effected, organize those 17 shots into discrete folders with subfolders of the iterations. One subfolder should hold the original archival frames, another with your compositor generated output. In the VSE, you can switch between the versions by re-linking your media to the iterated versions.
Note that where a shot overlaps another shot in your edit, you'll need to effect one, several, or all shots in the overlapped sequence individually. This will require dumping all of the frames for each shot involved in the overlapped sequence. For example, if ShotA consists of 200 frames and dissolves for 30 more into ShotB, which is 70 frames plus the 30 overlapped, you'll want to keep those shots on separate channels so you can dump the full 230 frames (200 + 30 overlap) from ShotA and the 100 (30 + 70) frames from ShotB.
Complete all per-shot visual effects.

Grading

After all visual effects are touched on, you should have an iteration of your motion picture with all archival shots in place, including the newer highest quality visual effects. You can re-link against the same strips and "reconstruct" the final picture. From there:

Keep all temporary effects and adjustments on separate layers. We are only interested in the highest quality archival frames, untouched. Use the timings and adjustment effects as part of your blueprint, perhaps via markers in your timeline.
Export all of the frames for your entire project, with black slugs in between. In the old, dark ages, folks would use junk fill on their workprints when preparing for a negative cut. This approach is similar in that it uses black frames where the current reel isn't being utilized. The key is that each reel is precisely the full length set of frames of your final work and remain perfectly in sync.
Load your picture locked set of reels into the compositor, or utilize scene breakdowns to work on smaller sections. One reel per input node.
You can then use a few mix nodes to reconstruct your edit for grading and proper linearized adjustments for grading etc.

[1] It should be noted that in rendering circles, the terminology is flipped. That is, an offline render is considered the best quality render possible.


Subsurf ruining seemingly clean topology?

You need to add some "loop cuts" and slide them close to the edges where your mesh is joined. You may also have some z-fighting going on. Meaning faces that are occupying the same space.


I have Eyelid bones set up (and working) in Blender, but I can't figure out how to control the bones in Unity

The answer is that you use Pose Mode to create Blendshapes and then export the model with those Blendshapes into Unity!! :D


Script to change Text Editor font display so Symbol Fonts and Extended Characters can be referenced

You can enable International Fonts in CtrlAltU> User preferences > System to display special characters:


Code takes more time to run the more complex the scene gets

This is a common issue related to unique name lookup.

When an object is added to scene, blender ensure the name is unique.
So the more objects you add, the more time each one require for the name lookup.


If you eneable Backface Culling from the Properties panel you will see that half or your heart has its face normals pointing inwards.
Also the edges you are trying to bevel have duplicted Vertices.

To fix your beveling you need to do as M.ardito suggested:
With all of the heart selected Recalculate Normals and Remove Doubles
If you now select that edge and use the Bevel tool it will look alot better, but.... if you look closely there is still a little problem area.

To correct that anomalie Patdog has given the solution,

Select only the top faces of the heart and using the Insert tool (keyboard shortcut key I ), insert a inner edge loop on those faces.

Now you can go back to using the Bevel tool and it should bevel ok.
The extra edge loop on the top face can now be deleted ( X > Edge Loops )


why is playback really slow, but scrubbing really fast?

When you manually scrub you´re forcing the playback to update on current frame. But when playback is set to play by default it will calculate vertices, deformations (armature) and other effects.
If you´re on 2.79 blender, make an OGL capture from the Render menu or by pressing this icon:

That will render a capture sequence to the OUTPUT directory you´ve set your files to OUTPUT from on your properties->scene->render output on your blender file (panels to your right side of the screen).

Thank you for your consideration to vote me as the answer by clicking to the left :the icon with a check mark and upvote this answer.

BFCT_Schiller


Uninterpretablity in depth maps: why the pixel values do not necessarily represent a valid distance?

As @troy_s suggested, PNGs are not suitable for this use. PNGs are more suited to image color data only. For depth information you should use a format such as Open EXR. This can be achieved easily by simply changing the depthOutputNode.format.file_format = 'PNG' line to depthOutputNode.format.file_format = 'OPEN_EXR'.

The resultant image should now contain the correct depth information. For example, it can be loaded into the compositor, normalized, and passed to a Viewer node as shown :


Microdisplacements with adaptive subdivision turning black

When using adaptive subdivision, your normal map node should not use tangent space, or your object will appear black. Instead, use object space, and it will render as expected.
Object Space:

Tangent Space:

While I am not certain of the reason for this behavior, it is marked as a to do item in the tracker at the moment, rather than a bug.


how do I add a shadow on the floor of a tracking scene?

You must search for: Shadow catcher.
The blender will improve it in future versions but today we have to use two objects as you did, render the object, the ground without the shadow and the ground with shadows then use the node editor to join all.
The main object in the Layer 1, the ground in the second Layer.
See it bellow...(names in Portugese, my main language)


So after a while I figured out why it wasn't working: the name of the new family ended with a number. For instance, MballTwo works while Mball2 doesn't.


Looking into your file, this is caused because there is an existing animation starting from frame 1.


Similate a vessel being filled with a liquid

If you just want to raise the liqud level, you can have the inner shape with a volumetric material sat up as water and then make a cube and add wave modifier to it. Then add a boolean modifier to ineract with the inner shape of the Vessel. Then animate the cube to rise up in Z direction. (The inner shape of the vessel must be seperated object from the vessel) Also I suggest to retopology the mesh, it seems that there are some n-gons in your mesh that are causing some shadowing problems or could be wrong sided normals...


Is Blender the right software to make 3D animations of Mechanical components and assembly?

If you are looking for an actual force driven physics based simulation, Blender can be limited in that area and is probably not adequate for what you are seeking.

Bullet, the physics engine behind Blender is quite capable but not very suited for mechanical workings, and tight fittings and chained interactions like mechanical parts do not work well there and glitch out very easily.

On the other hand, if you don't mind a geometry/maths based solution, then Blender it sounds right for you, and Blender should be perfectly able to do what you see in the video. If you are looking for illustrations of mechanical parts and animations of simulations the constrains system should be quite adequate and easy to set up.

You may want to look into constraints based animations tutorials
See:

Precise Mechanical Rigging (Intuitive method)
How to animate winding a ribbon onto a cylinder?
Rigging an umbrella-like object
Is Blender a sensible environment for making a first-person orrery?


Particle system to individual objects with keyframes

Mesh with Collision Physic can kill particles. Add a particle killer mesh and turn of it's render visibility.


The 1st set of nodes (add and subtract nodes) are used  for offset the coordinate .. it is 3*3 convolution filter ..so it can use 9 voronoi/image texture ..so if you adds 0.5 in one of the add node , 1 texture will offset  0.5 unit scale..
If you add/subtract 0 in those node that means that node will not offset .there are 2 add node because 1 is x axis and other one is y axis.
So if you mute those 2 add node it doesn't matter cuz it is not offseting anyway...soorry for my bad English


The correct way to apply a pose of a rigged character is: pose the model in its desired rest pose; select the mesh and apply its armature modifier; select the armature and in pose mode select all bones and press Ctrl A "Apply pose as rest pose"; add to the mesh a new armature modifier, pointing a the armature rig.
This procedure will not affect the weights, but can destroy any previously made animation.


Combining two shaders, one with color map, one with a specularity map

You want to use a mix shader (or sometimes an add shader) to combine multiple shader nodes in the node editor.  The mix shader node will combine two shaders based on a given fraction.  The fac value determines the amount of the second shader in the output.

For instance the following will result in a 20% glossy (and 80% diffuse) material:

You can even use something else, such as a map or input node, to control the mix factor variably across the object.

Here I have plugged a specularity map into the factor, lighter areas on the map will receive more gloss, darker areas will receive more diffuse.

And here I have mixed in another glossy shader using an input > fresnel node as a factor, this will make grazing angles even more glossy (which is more realistic).

Note: to add a node hit Shift+A and select the node you want to use.


whenever smooth vertex is pressed it breaks up mirrored objects

You are doing this:

Cutting a cube and sticking a Mirror Modifier on it.

Then doing Ctrl+V, and picking 'Smooth Vertex'

This produces exactly what you show, and that's exactly what we would expect.

Smooth Vertex tries to pull all real vertices together. As mentioned in the docs

  This will apply once the Smooth Tool.

You must remember you are performing this Vertex operation on only half a cube, (the rest is mirrored) and therefor the real center of all these real vertices (shaded in orange) lies within their collective coordinates, not on the mirror axis - the mirrored portion is not taken into account.

Objects with a bit more definition tend to smooth much more subtle, retaining much of the silhouette and scale.

I think your main confusion was that you where performing this operation on an object that relies on a Mirror Modifier for half of it's visual geometry. Maybe you are looking for the Laplacian Smooth deform modifier. (which will work ontop of the Mirror Modifier)

Or perhaps the Subdivision Surface Modifier.


Copy Physics to multiple objects in Blender 2.8

Select your objects to copy to and then the object to copy from.

Then search F3 and enter the search string as "Copy Rigid Body Settings"

Or from the Object menu Rigid Body->Copy From Active

You can also right click this menu and Assign Shortcut to assign the action a key press of your choice.


Armature distorts mesh on transformation

Finally (after 3 days of debugging)

Somehow my wing plane get extruded (i guess)
so there was 2 planes on the exact same position, but the vertex group only moved the one behind the other.


Why does a box appear when I try to make a window hole in a wall using Archimesh?

Look at the settings for the "CTRL_Hole" object: if that object is renderable ("camera" icon in the last column not grayed out), you'l see it in the render. The hole for the window will be present, just hidden by the Ctrl_Hole object.

You could also try the other 'solver' option in the boolean modifier.


Two Materials on Object - Only One Material is Rendering (Cycles)

Isn't that like material is there, but is hidden under hairs because you have set in Properties >
Viewport Display > Amount like 10% of hairs, but 100% is rendered?

If Susu is right, I will delete my A.


How to hide light object keeping the Light effect?

You can disable light objects visibility from the Overlays popover.


Is it possible to get rid of these shading artifacts for a smooth shaded flat surface?

Proper Topology

Having a proper topology depending on the kind of work you are doing solves this problem

as here blender doesn't have enough info to shade the front face correctly

you can check the CGCookie guide for clean topology here


Can I combine translucent, SSS and diffuse shaders using the light path node?

The Translucent and Sub Surface Scattering shaders produce only an approximation of what is actually a volumetric effect - of the light scattering throughout the internal volume of the material - and this makes it difficult to combine them realistically. You cannot use the Light Path node for this as there is no Light Path that can distinguish between SSS and Translucent paths (since they are both emulated as surface shaders, not actual volumetric rays).

Instead, use a Volumetric material mixed with the surface Diffuse. This allows the transparency of the surface to be adjusted and also allows the volumetric density and scatter/absorption to be adjusted to get the desired effect.

Here's the material :

Adjust the mix node to vary the surface Diffuse/Transparency. Adjust the Value node to affect the volumetric density. Vary the Diffuse shader to affect the surface color and the RGB node to affect the volume.

This can produce the following effect (note the hair roots showing below the surface) :

(Example produced using Branched Path Tracing inteegrator, increasing the Volume samples (to 6) and similarly increasing the number of Volumetric Bounces in the Light Path properties)


instance objects according to list of discrete times (via csv, json, etc) in animation nodes (or just with python)

If you can feed data something like this:

We can convert this data into a Generic List using eval() in Expression node. After that we can iterate through this list using loop and do whatever stuff you want there. Here is an example:


You should loop cut (Ctrl+R) or edge slide (G+G) first

And then, there'll be some options. Then, check the Correct UVs

After the modal tool is run the Loop Cut and Slide Options. These options are available in the Adjust Last Operation panel.

https://docs.blender.org/manual/en/latest/modeling/meshes/tools/loop.html
https://docs.blender.org/manual/en/latest/modeling/meshes/editing/edge/edge_slide.html


How to refresh F-Curve colors via python?

I think that the fcurves colors are calculated when the graph editor tries to read their value for the first time, so you may have to do that yourself :

for action in D.actions :
    for fcurve in action.fcurves :
        index = fcurve.array_index

        if fcurve.color_mode == 'AUTO_RGB':
            h = float(1.0)/3.0
        #I don't have the right formula for rainbow
        elif fcurve.color_mode == 'AUTO_RAINBOW':
            h = float(1.0)/4.0

        fcurve.color.hsv = (index*h, 1, 1)


Is there any way to reduce the spaces between UV islands without scaling the actual islands?

When you press Ctrl+P move your cursor or let your cursor be in 3D window and press F6. A popup will appear - play with the settings there to adjust how much spacing you need.


Is there a simple tool for fixing invalid geometry in edit mode?

There is an addon called BoolTools that can help with this.

It's a two step process.  First select the entire mesh and separate by loose parts, then union the component parts.


What is a paint slot (compared to an image with a UV mapping)?

A texture painting slot is how you can control which is the active target for paint without having the node editor open to hunt and find that corresponding image node to click it to make it active, nor having to find the corresponding texture in the material texture properties.

The origin of the texture slot panel was actually a GSOC adaptation of the Texture Paint Layer add-on that offered similar functionality in the N Panel, and it also gave the ability to not need the properties editor to be open to determine which image texture was to be the target.

Masking is much more than the Stencil type that is normally used between image textures, and the actual mask tool is very powerful and I have explored it a few times on my youtube channel. You can utilize a different UV projection for masking, or you can use the same as the existing UV mapping for the target image.


Blender runs out of memory while rendering fabric hair on GPU

@Wiirexu That simply means that the 2GB of VRAM you have on your GPU is not enough for the scene. If you want to render the scene using your computer's available RAM, you have to render with CPU. If you render with CPU and there is still not enough memory, your only options are to get more RAM, or use a render farm.

You do not have enough VRAM available on your GPU for rendering the scene you are trying to render. Your only other options are:

You could try reducing the amount of geometry in your scene using the decimate modifier.

You could switch to CPU rendering. This will render your scene using your available RAM, instead of VRAM.
(If you render with CPU and there still isn't enough memory, you will need to add more RAM to your system.)

You could use a renderfarm service, such as SheepIt! (Free)

You could upgrade your current GPU or add another to your system.

You could ask someone to render it for you (I'd probably be willing, I've got 6GB of VRAM)


Animation Nodes: Copy a selection/group of objects

I can only recommend creating everything explicitly. So your node structure should be something like:

Instance all the objects you want, possibly using the Copy All Option or by disabling the Copy From Source option and injecting the object data later.
Loop over all your objects, add missing modifiers as described in my answer here, and set modifier values using Attribute nodes.


How to scale and move a mesh to specific location and axis in Blender 2.8

Welcome to Blender Stack exchange! It appears that you are in edit mode and want to move the shorter plane near to the larger one(as described). You can just select the plane and move it using G hotkey, but make sure you are not selecting anything else other than the plane. You can go into edit mode > deselect everything (Double tap A or Alt A) > hover over the plane you want to move > press L to select that plane > use the move tool to move in the choice of your direction. I would recommend you to see some videos of Blender Guru, CGGeek, CGCookie to get started with blender.


Can't Get New Intel Denoiser to Work on Projects

You have to plug the "image" output of the denoiser into the "image" input of the compositor.

Remove the link from "image" output of "Render layers" entirely.

Loaded it up, and it works flawlessly.
FYI: The intel denoiser doesn't kick in until after the image is fully rendered, and takes 3-5 seconds to clear it up.


Bge Python: Move objects along one axis using mouse movement

Simple script, need more work but its good start.

from bge import logic
logic.mouse.visible = True
def main(cont): #cont = currentController
    cont.owner.worldPosition.x = logic.mouse.position[0]**2 # owner likely the cube

just add a cube and in logic nodes add always sensor + python controller.

EDIT

"logic.mouse.visible = True" show the mouse when bge its runnig so you can see the mouse position on screen.
For clarify: my script name is "script.py" so im using python controller to run a module name main from my script ("def main()"), so every tick it run main().

You can avoid this setin python controller to run script and not module:

and the script should be like this:

    from bge import logic
    logic.mouse.visible = True
    def main(cont): #cont = currentController
        cont.owner.worldPosition.x = logic.mouse.position[0]**2 # owner likely the cube
    main()

OR just this:

from bge import logic
cube = logic.getCurrentController().owner
cube.worldPosition.x = logic.mouse.position[0]**2

so this script NEED MORE WORK, to get it work like you want you need to work on it, and dont need to learn a bunch of things.

And for the last tip. mouse position go from 0.0 to 1.0 and when mouse position its > 0.5 will go to the left of the screen (your right) and the other way if its < 0.5.
Finally if you show your work and not just and example without trying yourself to solve it, i cant help you anymore because the idea its to you learn something and not just copy.


Is there any way to activate Rigify Buttons from a Python Script?

Well, I guess I'll be answering my own question!
After reading up the barely commented documentation, I figured out how to do this. It's very likely that what I have done is very inefficient, but it works. Here's the code I concluded with!
RigGen = True #Just in case I don't want to replace the rig every time

#Define a deselect command for all selected items - it'll be useful later.

def DeselAll():
    for obj in bpy.context.selected_objects:
        obj.select_set(False)
DeselAll()

##Then, we delete the original widgets found in the "Widgets" collection
if RigGen == True:
    widg_del = bpy.data.collections["Widgets"].objects
    for obj in widg_del:
        bpy.data.objects.remove(obj)

    #Then, we removes all orphans stored in the meshes data block
    for block in bpy.data.meshes:
        if block.users == 0:
            bpy.data.meshes.remove(block)

#At this point, the context has been changed, so we need to change it back to object mode
#Else, our rig generation will not work unless you hover your mouse over the 3d viewport.
    bpy.ops.object.mode_set(mode='OBJECT')
    cnt = bpy.context
    scn = bpy.context.scene
    mrig       = bpy.data.objects["Metarig"] #"Metarig" is your metarig object name
    mrig.select_set(True)
    rigify.generate.generate_rig(cnt,mrig)

DeselAll()

It's slow, but it's faster than doing it all manually!


How to position a vertex by inputting numbers and make other vertices move relative to it

It's more comfortable to use Object mode with its snapping tools in order to move object only on one global axis. However editing certain vertex is done in Edit mode.

A way to workaround (see below as to why) is to use Hook modifier. It will allow you move object which vertex is hooked to in Object mode while all other vertices will follow it after you set up the modifier.

Enter Edit mode, press Ctrl+H, in the opening menu choose Hook to New Object (it's more convenient to use created new empty for that).

While still in Edit mode, choose vertices you want to be moved with the "designated" one and click Assign in the Hook modifier settings.

Now the "designated" vertex will be in the same place as empty and follow it, and all other vertices will follow the empty.

However you still need to choose proper axis to move along (G > X > ... etc) or use snapping to cursor which is moving along all axes. Here's why this is a workaround  - you can move 3D cursor anywhere, switch Pivot Point to 3D Cursor, select hook-empty and scale it to 0 along desired axis.

Hooked object will turn into ugly flat rug, but it's easily fixable - just reset scale of the empty with Alt+S.


This is most likely caused by incorrect normals. In order to correct this, go into edit mode, select all the faces, and click on Shading->Normals->Recalculate.


How to attach a texture to an imported .stl file

Similar issues have been asked many many times before, see .fbx export why there are no materials or textures? or Issue with Importing 3D Models into Blender

The STL file format doesn't support textures, its a geometry only file format suited for 3D printing and computer based fabrication processes.

It doesn't include any color or texture representation structures, as far as I know it doesn't even support UV Coordinates.

UV coordinates are what is needed for 'wrapping' a 2D texture around a 3D mode, they can be either automatic, or obtained by UV Unwrapping

There is no such thing as '3D textures', at least not in the way you mention. Those are generally either procedural textures or voxel based textures for volumetric data representation (like smoke or sparse mediums)

If your 3D printer does indeed support color information you will have to look into its documentation what file formats it supports and what it uses for color information. And you will most likely need a separate image file for the texture.

Edit: Ok I think there some confusion and wrong terminology use here hence the misunderstanding from my part.

What you downloaded is not a 3D texture (textures are images with color information), it's a 3D model of a stone pattern albeit one achieve with an image texture through displacement, but that is irrelevant.

If you want to wrap it around in a cylinder shape, forget your STL cylinder, it is useless, its probably easier to just do it from scratch.

Use the .blend file from the download archive, open it, apply Displacement Modifier, then add a simple Deform modifier set to Bend.

Add a an empty object, rotate it -90 degrees in X axis and use it as a origin object in the Deform modifier.

Increase the angle of the deform modifier until it wraps up into a cylinder.

Now it's only a matter of closing the caps and removing doubles so that it forms a manifold closed shape.


how to make an object blend with the background without looking fake?

I think it's a problem of contrasts, you need to either:

Push up the black levels of your planet

Or decrease the medium values of your background so that the 2 elements work together.

Also, maybe it's weird that some fresnel comes on the edge of the planet that faces the darkest side of space, try to rotate it (not sure about that but it may work on the perception)? And add some stars?


how to change a mesh given by mathematical function with time i.e. how to include the time parameter in the mathematical equation?

I would suggest using Animation Nodes for more interactive results.

The Grid Mesh node generates evenly spaced vectors (Which can act as your 2D coordinates plane).

I separate the vectors into their x,y,z components (Z is zero in the grid), for every vector I compute the equation you provided above in terms of the x and y values I extracted, then I form a new vector from the x, y and z where z is the value we computed, resulting in points that satisfy your function:

In order to make it a 3D mesh with faces, we use the original polygon indices and new vectors to make a mesh as follows, this is just how meshed are output to object:

Last step is to introduce the (t) in your equation, which will be time, we can use the animate float node with the starting and ending values -1, 1 respectively as you stated in the question. And of course Duration is the duration of the animation. Resulting in the animation as you see:

If you want to color the surface based on its z value, where the higher the point is the higher the red value and the slower it is the bluer it is, you can use the following shading node tree:


How to connect the vertices of two separate objects?

Could you not work with one eye and your faced joined up and mirror afterwards?.

Highlight the eye vertices in edit mode with  with C or B then separate by selection with P and apply the mirror to new object creating your second eye. As long as it lines up nice it would get you your mirror option back.


Collision logic brick not detecting collision in BGE

Is your character have "Static" physics?
If yes,just change character's physics to "Dynamic"


how can i offset a gradient in a colorramp

You can use the the Mapping Node, add it with Shift-A>Vector>Mapping

You edit the location to move it. You may have to try negative values.


You have weight painting problems. Here's how I found the first one:
Go back to object mode and select the model.
Go into edit mode.  Select solid view and xray:

deselect all with ALT-a
In the Properties editor, in the Object Data Tab, go to the Vertex Groups area and select one of the relevant vertex groups.
Press the select button.  The vertices that are in that group become selected.  Here, for example is the model with bicep.R selected:

Keep doing this and you will eventually come to forearm.R:

Select it and you get:

Since the left forearm vertices are selected, they will move when the forearm.R deformation bone moves.
In this case, a simple fix is to manually deselect all of the vertices that should stay in the group.  I used circle select with middle mouse but there are a lot of ways.

Next go to the vertex group and click "remove".  This will remove the remaining vertices from the group.
as you can see that partially solves your problem:

What I did isn't the usual way of fixing this sort of problem.  Normally you would use weight paint mode.  It looks like you have a lot of related issues so you might want to find a tutorial on weight painting.


Hold Ctrl+MMB  and drag left or right, or up and down to increase or decrease the size of the interface.

This works on many (but not all) of the 'areas' in blender, like the Graph Editor, Image Editor or the Properties area. It also works in the 3D view Toolbar (T) and the Properties toolbar (N).


Is there a limit past which bigger textures has no effect?

Yes reducing the resolution of the textures will eventually make the pixels large enough to notice, but will improve performance.
Compressing one map and not another depends on your node setup or in a external application it's limitations, but it should be fine.


Can you make a bump map texture emit light in Cycles?

You can use an emission node, with a mix shader node (use the map map for the factor input). Now your object will emit light based on the bump map.


It looks like you need to recalculate the normals: select all in Edit mode and ctrl N


Is there any principle about using "edge loop" when building a model?

There are so many ways to solve this depending on your end need. I think it's important to be pragmatic about how you spend your time modelling. If it looks good then it is good. Simpler topology can make it easier and faster to model and also quicker to render. Model much, do many misstakes and learn from them.


Automatic weight paint failure on only one side of rig

It turns out that the normals were flipped on the left arm. I flipped the normals back, re-attached the mesh to the rig with automatic weights, and it worked perfectly.
I'm still getting used to Blender 2.8. Had no idea the normals were flipped.


Joining seperate meshes that are parented to bones to single mesh

"I don't want to have to do an armature deform and then have to paint each part hard red/hard blue, unless there is some non-manual way to do it (?)."

Yeah so I ended up doing that but found some tricks that made it take barely 5 minutes (for ~20 bones).

Here's a guide for anyone who is in the same situation I was in.

Select all of your meshes and Alt+P to unparent without transform
With all your meshes still selected, join them with Ctrl+J
If you've posed your mesh, select all the bones and Alt+G and Alt+R to reset pose
In object mode, select your conglomerate mesh and the armature and Ctrl+P to parent them, selecting Armature Deform with Automatic Weights
To optimise the repainting process:

a. In Weight Paint mode, set your brush to Draw, and set the Weight and Strength of the brush to 1

b. Next to the brush's Strength slider, there is a dropdown called Brush, in it, disable Front Faces Only

c. Next to the Mode dropdown (where it should currently say Weight Paint), there is an icon of a cube with a highlighted face, hovering over it should say Paint Mask; enable it
Flipping back to Edit Mode, select a face of the loose part of the mesh you wish to paint, and hold down Ctrl+[+] to Select More until the full part is selected
Back in Weight Paint mode, select the corresponding vertex group of the part you selected.  Everything but the corresponding mesh should be wireframe (this means the Paint Mask is working)
Paint all over the part until it is entirely hard red
Hit Ctrl+I to invert selection, turn the weight of your brush down to 0, and paint over everywhere else until it is all hard blue
Rinse and repeat from step 5 with each part, remebering to flip back your brush's Weight to 1 each time

As we say in the industry, bada bing bada boom.

Once you get into a flow of things, you can do your whole model super quick because unless you have a very intricate mesh, there is no precision involved, you can stay in one view the whole time.

Hope that helps anyone else!


Followed Blender Guru's Geometry Node tutorial (gumdrops), have some issues with how it looks

This is the screenshot from the tutorial.
I marked things that are wrong in your setup.


Some quick tests show that blender is designed to work with objects that have high vertex counts but not really with a large number of objects. Even with 3000 objects in a scene it takes a few seconds to select all objects, yet selecting the 33,000 vertices of those objects all joined together is almost instant.

I tested four ways to create multiple cubes.

Create 1000 cube objects - 8 seconds
Create a single mesh containing 1000 disconnected cube meshes - 0.5 seconds
As 2 then separate by loose parts to get 1000 cube objects - 5 seconds
Create a cube and a grid with 1000 verts, enable dupliverts and make real - 0.6 seconds

I am thinking your best approach would be to create a mesh that is a single plane with a vertex where you want each cube to be located, enable dupliverts, then if you want them separate for rigid body you can make the dupliverts real.

For info the script used to test these times is here.


Weight painting stuck in some kind of weird mode

This is a mode called Paint Mask. While in Weight Paint mode, go up and look at the top left of your 3D View, and you'll see a button with a face icon on it. You will likely find that it is activated. Turn it off to go back to normal.

The way that this mode works is that whatever faces you select while in Edit Mode will be the only faces that can receive a brush effect while in Weight Paint mode. It's very handy in this regard. A good feature, to be sure. But it can be activated by accident, and lead to frustration. If you go into Edit Mode for the object you're trying to weight paint, you will probably see that the same face that is showing up blue in the pic you provided is already selected. Even if you unselect these faces, though, you'll still need to turn off the paint mask in Weight Paint mode. If no faces are selected in Edit Mode, and the paint mask is still on in Weight Paint mode, then you won't  see any weird blue faces, but you also won't be able to paint at all.


Create Additional Curves Morphing Between 2 Input Curves

This will work only if both initial and final morphing shape have the same number of vertex.

If they don't you can always add a few more to the one with the least vertex, if moving them in place is not too much of a hassle.

Then create one single curve, shape it as desired.

Add two new Shapekeys to it, one Basis and one with the desired final morphing shape.

Now make a few copies of the curve (non-linked clones), and on each one gradually increase the Value for the shapekey.

For an even constant morphing divide the percentage by the number of "snapshots" you plan to have.


That's the reflection of the table. Try hiding the table/plane object and take a look.

Edit to address followup question;

... Technically, yes, you can disable the table in the reflection. Start by switching to the Cycles rendering engine (and make sure GPU is selected if you have a GPU capable of supporting Cycles);

In the Object Properties, Under Visibility -> Ray visibility, uncheck "Glossy";

The result;

It should be noted, though, that this will produce a highly unrealistic result in your final scene.


Had same problem on Ubuntu - 2.8 didn't want to start up. 2.79 however works fine. This problem may be caused by GPU requirements. I had this problem on a laptop with an integrated GPU...


Combining materials that already has UV coordinates

I know there is an addon for that: TextureAtlas.


Can I save blend files with lzma instead of gzip?

The GZIP compression is currently the only compression format considered when writing or reading a .blend file. A single reference to LZMA in Blender's code is for compressing point-cache files, with accompanying caveat:

"Effective but slow compression"

... something we wouldn't consider as primary choice, for dealing with potentially large .blend files.

I think your best bet is to write export/import operators, utilizing external LZMA (de)compressor.


Why is lighting broken while using shade smooth?

The normals of your faces are pointing in opposite directions, possibly due to a scale by -1 ?

AltN > Recalculate Normals (outside) fixes that.


Blender Game Engine not displaying World texture

I can't actually find anything which says that sky textures are unsupported in the game engine, but there are a lot if things which are unsupported in the game engine..

One thing you could do instead is use a skydome, which is basically a UV sphere  with a sky texture mapped to it.

Add a UV sphere and scale it up so it covers your entire scene.
In edit mode, select everything (A) and press ⎈ Ctrl⇧ ShiftN to flip the normals.
To avoid extreme distortion around the poles, you can make infinitely small holes in the top and bottom of the sphere.
In top view (Numpad 7), select the polar vertices. Press ⎈ Ctrl⇧ ShiftB and type in a small value like .001. Press ⏎ Enter and ⌦ Delete>Faces to delete the new faces at the poles (creating holes), then press S 0 to scale the holes to infinitely small points.

Make sure the vertices are not merged when you do this, otherwise you'll be back where you started.
From side view (Numpad 1), press U> Sphere projection and enable Scale to bounds in the redo panel (F6).
Add a material to the skydome and enable Shadeless under materials > Shading:

Add your texture with UV projection:


After parent bone with another bone, why my bones and mesh only visible in edit mode? No constrains

It seems like a Beta version problem, I rigged it in Blender version 2.83.
And I tried to rig it from scratch in version 2.82, It's completely no problem!


You're probably looking for a Rip Fill option. Select the vertex, then press Alt+V (or type it via Spacebar menu). Then you can slide the vertex (by taping the G button twice) and delete the unnecessary edges using the Edge Dissolve option (X).


objects in scene are not appearing in final render but are in render view - cycles

I think I know what is going on but it may not work in that version but if it does:
This is a very common problem and easily fixed, firstly go into the top right and open an outliner window.
Then that window should show which parts of the render are visible, if not open the tab shown here
This will then reveal which items are included in the render and which aren't by a greyed out camera icon.
Change this icon to the non greyed out camera and the objects should appear in your render.
Good luck!


How to set grease pencil general default properties across scenes

MTKay,
I am just going to make a suggestion,
But have you tried to make a full copy of the Scene.
Scene > New

Scene > New > Full Copy

I would certainly learn about the concept of linking and appending Libraries. I believe these might be the missing piece to your adventure with Blender.
https://docs.blender.org/manual/en/latest/files/linked_libraries/index.html
I think after you make it over this issue....your time will much more fun!!
Happy Blendering!
We all learn by sharing what we know!
Smartdog


Animation with a slow start and quick end

Design an acceleration curve in the Graph editor.

Select the object that needs acceleration.
Open a Graph editor window. There will be lines plotting time against function (location, rotation, scale).
Select a keyframe point and press "v" on your keyboard. You get a dropdown menu that gives you vector behavior choices. (In my example, I selected my last keyframe, hit "v" and selected 'vector', which gives independent control over the incoming and outgoing bezier arms).
Adjust the function curve to give you the acceleration curve you're after.

Constant speed is a straight line.
Acceleration starts flattish on the left, and grows increasingly steeper.
Deceleration starts steep, then gradually flattens out.


Uploading an object from Blender to UE4 looks different

I experienced this same problem. Open Blender and go into edit mode by clicking Tab. Then you need to select all the faces, and use Ctrl-N to recalculate the faces' normals. Finally click that thing that looks like a wrench and click solidify. By doing that you're making every face solid like a room and that should work.


Sun lamp and Diffuse surface is not lambertian?

Assuming the sun light has size 0 and strength 1, the correct maximal value on the sphere is 1⁄pi, because of energy conservation and the units used.

Cycles uses physically based units for light strength, in this case Watts⁄m2 for sun lights. Other renderers and game engines (typically ones that were not designed with physically based rendering in mind) often use a light strength that is implicitly multiplied by pi, which would give the maximal value of 1 you expect.


There are many different ways. This is one of them (maybe not the best, but should be easy to follow):

Create a cube
Resize the cube to match the size of the pool ( s )
Apply your object's scale( Ctrl-a > Scale)
Go to edit mode (TAB)
Press 3 to switch to "face selection"
Select top face
Inset the face i
Select the inner face and extrude vertically with e + z (so you can create the "hole" in the swimming pool
If you want to change the width of the walls you can select inner faces (check screenshot) and resize them in both X and Y to get your result ( S-x and S-y)


How do I remove the line after merged the 2 objects together?

I would go into edit mode and look for duplicate vertices and merge them. Then check your edge flow and see if those that are there need adjustment, and maybe add/remove some loops in that area. It looks like it's really pinched in there, which is streatching the existing polygons, which in turn stretches your shading. AS a low poly model it won't do much, but as you subdivide, Blender will make calculations based on the existing geomotry that is there, so that's where I would start. Good luck :)


How do I fix the unwrapped version of my knife?

When you unwrap objects, there is a slider for the "Margin" that you could use. Another things is that even if you cut the same areas as in the tutorial, probably some parts will have a different orientation; that could be fixed manually with rotation
Example:


Dimensions won't get updated via bpy script

The solution is to call bpy.context.view_layer.update() after loading a new font in to the text object.


In 2.80 the panel to adjust the last operator has been moved out of the toolbar region into a floating panel at the bottom left of the viewport. This can be expanded/collapsed by clicking the top of the panel.

There is an option to hide this panel, it can be found in the 3D viewports View menu.

Even if the last operator panel is hidden, we can still bring it up manually with F9 - note that in 2.79 we use F6


Soft lighting through translucent material in cycles

Here's a scene before the curtain. The only light is an emission plane outside and over the window.

(clik on the images to enlarge)

If we add a translucent curtain we get a lot less light illuminating the room.

Adding transparency will allow more light into the room, but will make the curtain "see-trough".

Controlling the transparency so that is not visible to the camera will make the light come into the room while keeping the translucency of the curtain's material:

By changing the ray depth values you can control how much light comes into the room:

Alternatively

You can just turn the whole curtain into an emission object unseen by the camera:


What does this red line across my shader node mean?

That means the node is muted and isn't taking any part in calculations. To unmute it, select the node and press M


sculpting and connecting from different bodyparts

One option is to use the Boolean modifier:
Let's say that you wanna connect one arm to the torso (this will be the main object):
0.- (Optional) Select the arm, go to Object properties > Viewport Display, select Wireframe and change the "Display on" to Wire.
1.-Select the Torso, go to Modifier > Boolean : Change the "operation" to "Union" and in "object" Select the Arm.
2.- Click "Apply" and turn Off or delete the arm Object.
Now you have one Object made with the torso and the arm.
Repeat that with every part that you wanna connect to the torso and after that, add a subdivision and apply.

Hope that helps.


Retopologizing is recommended often, but the truth is, retopologizing is an enormous amount of work, and many people lack the skills to do it properly. For this reason, there are often paid add-ons that help a lot, such as Retopo Flow. Assuming that isn't an option, there may be something you can do, but could be quite tricky, and there are no guarantees, since Blender has no dedicated and complete retopology solution right out of the box. But it does have the Remesh modifier. Admittedly, I haven't gotten that to work very well in my own work, largely due to me being baffled by all its cryptic settings. But I've had more luck with a newer option called Quad Flow Remesh. However, I only ever came across it in Blender 2.81, and even then, I had to use the search function (F3) to access it because it didn't yet have a location in the UI. I'm using 2.82a currently, and this feature doesn't seem to be accessible the same way. It might have been moved. I seem to recall finding a similar tool in the Active Tool properties panel while using sculpting brushes, but I can't be sure that was the same feature. If any one knows about this tool or its whereabouts, I'm all ears.


Bake hi-res diffuse texture onto low-poly version problem

So I basically answered my own question. I just did a quick test on using the ray distance setting and it completely worked. See image above for results and instructions.

My apologies, I'm new to using this site as a member and had no idea where the 'answer question' button was located.


How to use normal displacement instead of vector displacement in shader editor (2.8)

Figured it out: Use heightmap for the height value in a displacement node, use the output of the displacement node as displacement.


How to make field focused in props dialog

Just rename the operator property name to type. Honestly, I don't know why this works, maybe some kind of super secret feature, I don't know. Credit for that idea goes to @p2or: Is there an addon for renaming an object with a keyboard shortcut?

import bpy

class OFPropConfirmOperator(bpy.types.Operator):
    """Generate Custom Output Folders"""
    bl_idname = "of.confirm_dialog"
    bl_label = "Generate Output Folders"

    type = bpy.props.StringProperty(
        default="Base",
        #options={'SKIP_SAVE'}
        )
    geo = bpy.props.StringProperty(
        default="Geometry",
        #options={'SKIP_SAVE'}
        )
    tex = bpy.props.StringProperty(
        default="Textures",
        #options={'SKIP_SAVE'}
        )

    @classmethod
    def poll(cls, context):
        return True

    def execute(self, context):
        #do some stuff here
        return {'FINISHED'}

    def invoke(self, context, event):
        return context.window_manager.invoke_props_dialog(self, width=500)

    def draw(self, context):
        row = self.layout
        row.prop(self, "type", text="Base Folder")
        row.prop(self, "geo", text="Geometry Folder")
        row.prop(self, "tex", text="Texture Folder")
        row.separator()

class OFPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_idname = "OF_my_panel"
    bl_label = "OF Tools"
    bl_space_type = "VIEW_3D"
    bl_region_type = "TOOLS"
    bl_category = "Tools"

    def draw(self, context):
        layout = self.layout
        layout.operator(OFPropConfirmOperator.bl_idname)

def register():
    bpy.utils.register_class(OFPropConfirmOperator)
    bpy.utils.register_class(OFPanel)

def unregister():
    bpy.utils.unregister_class(OFPanel)
    bpy.utils.unregister_class(OFPropConfirmOperator)

if __name__ == "__main__":
    register()


How do I create a driver with a random value and apply that driver to multiple objects?

You don't need a driver to accomplish this. Simply select all the rock elements you want to affect. Then use the Randomize Transform command and edit the XYZ Rotation values in the side panel.

This will give you a randomized starting rotation for each rock.

Now, with all the rocks selected, click CTRL+A and choose Apply Rotation.

Now we want to add a driver to the XYZ rotation values for each rock. We want this value to be constant throughout the animation. We can do this by using a multiple of the frame number.

First, select all the rocks and add them to a group named "ROCKS".

Then open up the text editor and run this script:

import bpy
import random

for obj in bpy.data.objects:
    randomSpeed = random.randint(1,20)*0.001

    for group in obj.users_group:
        if group.name == "ROCKS":
            for i in range(0,3):
                fCurveOb = obj.driver_add("rotation_euler", i)
                drv = fCurveOb.driver
                drv.type = "SCRIPTED"
                drv.expression = "frame*" + str(randomSpeed)
                drv.show_debug_info = True

This will set the XYZ rotation values to increment each frame. You can increase the rotation rate by increasing the 0.01 value.


It is listed under Select Similar which has a ⇧ ShiftG shortcut and can be found in the Select menu.

Note that the area option (and others face/edge related) is only available if face select mode is the only active selection mode, if you have multiple selection modes active you will not see the option.


I went to recycling this answer and after simplifying I end up with the same node tree, that seems to me is working. So I guess I missed something ... so if you can explain missing part closer.


AI Denoisers use algorithms to guess which pixels are fireflies, and what colour that pixel was supposed to be. The algorithms are limited to the data that it can collect from the Denoising Data and the surrounding pixels. Thus, if insufficient data has been passed to it (not enough samples), the denoiser will create a "washed out" effect where you're losing detail. In truth, the denoiser will almost always cause loss of detail, it's just that when the sampling is high enough, the loss of detail is negligible.

You haven't done anything wrong with the compositor nodes, you're going to have to increase the samples in this case.

If you're worried about render times, check out this video by BlenderGuru. It was created pre-2.80, but much of the content is still relevant.


Animations Disappear When Loading Up Blender

The F toggle is something many of us animators have complaints about. Yes it has to be selected to keep Actions if you start a new Action. The F toggle stands for Fake User. When you start a new Action via the Action Editor the Action that you had is removed from the Armature. As objects can only use 1 Action at a time.

The correct way to use multiple actions is to use the NLA Editor. There are new buttons in the Action Editor's Header: Push Down and Stash. You can use those to save your Actions in the NLA Editor so that they don't get deleted.


Dos window opens along with Blender application. Is it safe?

The console window is the main part of Blender. If you are lucky, try closing the dos window before it loads the Blender UI, you will see that Blender automatically closes.


Freestyle distance to camera modifier not working correctly

The cause of the reported issue is most likely the Range Max value you have specified  (i.e., 8.726).  Try to decrease it and you will see stroke ends get thinner.

I believe you have chosen the Range Min and Max value by means of the Fill Range by Selection button upon the selection of the sphere mesh.  I found a bug in this automated method and the distance calculation between the camera and individual mesh vertex locations was not correct.  A fix of the bug has already been in the official Blender code repository and will be included in a future release of Blender (likely in the forthcoming 2.79 release).  For the time being, the auto-filled values may not be accurate.  You might need to tune the values manually as suggested above.

It is also noted that the auto-fill method takes all mesh vertices into account when identifying the Range Min and Max value.  This means that not only visible but hidden vertices are considered.  Recalling that you have a wide angle camera close to the sphere mesh, only a small fraction of the mesh surface in the frontal part of the sphere is visible.  The auto-filled Max value is hence likely too large because I guess you actually expect the distance-based thickness only accounts for the visible part.

Try also to turn off the "Visibility" toggle in the "Selection by" section of the Freestyle Line Set panel, and you will see the line thickness is indeed at the minimum on the far (invisible) side of the sphere.

To make it easier to fill the Range values by taking only the visible part of the mesh into account, I also made an improvement of the Fill Range by Selection button so that in the edit mode only the selected vertices are considered for distance calculation.  This code revision has also already been in the code repository and will be available in a future release of Blender.


What techniques have been used to repeat geometry or other detail to the infinite horizon?

To give the impression of infinity, often it's not necessary to copy the object many times at all. you will notice that in the example image only about 8 or 9 repetitions are visible, the implied continuation of cubes is hidden behind a white glare.

One way is to do this is by using an array modifier. One issue with this is that it is not the most efficient, as the array modifier creates new geometry every time the source is repeated. To use the array modifier to make instances (references to a single copy of the mesh data, rather than actually copying the mesh data), e.g. using Dupli objects:

Add a plane (ShiftA> Add > Mesh > Plane) and add an array modifier to it.
Parent the object you want to repeat to plane (select the object, then the plane, and press CtrlP>Object)
Enable Duplifaces on the plane under Properties > Object > Duplication.

Using this technique, you can duplicate fairly high-poly objects many times. In this example I duplicated a 4500 vert cube thing 100 times without any trouble. When I tried this with a straight array modifier (without the dupliface trick) the viewport was quite slow and the array modifier took about 30 seconds to compute.

Cycles is actually pretty good at rendering large amounts of instances like this.

Some examples:

Fun with Instancing in Cycles
19 Billion Polygons, not a ridiculous number anymore (BA thread)

Note that depending on the scene, there might be other optimizations you can do, e.g. using baked texture maps and lower poly models for far away objects.


Material driver works, but doesn't update in viewport

After a long time fiddling with drivers and properties, I found a solution.

Create a custom property for the material you're manipulating with drivers

Add a driver to the property, and add your variables and scripted expressions to this driver

Reference the custom property in your node driver

Important: The intermediate custom property must be a material property. Custom object properties alone won't work.

Possibly related: Driver on material not updating.
Mainly the "not all drivers are created equal" statement. The issue I experienced is the inverse of what happened in this question, though.

For some strange reason, the existence of a custom material property with the script is what triggers the auto update. If you have two identical drivers with the script, one for a custom object property, another for a custom material property, and reference the object one, it'll work. As long there's an identical material driver doing the calculation, it'll work. You don't even need to reference it, it only needs to exist. Don't ask me why.


Removing black-ish tint in beveled area of clear glass

Here's a material fix that I applied that seemed to head toward what you were wanting. Same basic components, just re-arranged a little.

I think you can get your reflections back using a method something like this afterward:

If you want to get even more of the reflection back you can just keep the progression of your mix nodes, something like this:


To activate/deactivate proportional edit in edit mode, use O.

Alternatively, use this toggle in the top bar of the 3D viewport


Not really an answer as there is currently no solution to my specific problem in 2.79. But I did find some alternative to de-selection.

I have created a keymap based on the 2.80 "Industry Standard Keymap" proposal in case people ran into the same issue as me.

https://gist.github.com/bitinn/22f6fefe026d8d9e83468864edb8f835


How to improve the accuracy for a rigid bodies

Work smart, not ...

Okay, so you realized Blender bullet solver implementation is not as strong out of the box. Therefore we have to help it out a bit.

Reconstruct your geometry with simpler shapes. In your specific file, I could just create the crate out of 5 cubes (the walls and floor) which are then parented to the crate geometry.

Use simple rigid body shape wherever possible. I made the walls into Box colliders and the sphere into Sphere colliders.

Now, you realized, that the Steps per Second and Solver Iterations don't ensure a more stable simulation, if we just increase them. Here comes a workaround: We'll make our subframes into actual frames by slowing down the simulation and the speeding it up afterwards.

Scale the keyframes apart by 6. The box now moves 6 times as slow.
Adjust the speed of the rigid body simulation. I entered 1.0/6.

Adjust the playback speed. The fps will be 24*6 and the render steps can be 6. (Obviously the scene's end will have to be adjusted as well.)

Increase the Solver steps and Iterations as needed. I used [500, 500], as shown in the above image.

The resulting simulation is stable, although my computer can't playback a 144 fps.


Why should texture resolutions be powers of 2?

It's probably better to ask a question like this on a dedicated programmers Q&A site since people there are more likely to focus on these things.  Anyways, here are a few considerations that I am aware of.

When textures are not powers of 2, you(or the software you use) will usually have to use special extensions made by the hardware/driver manufacturers if you want them to work consistently.
For instance, OES_texture_npot or ARB_texture_non_power_of_two.

Using special GPU extensions to increase a programs abilities can also reduce compatibility since not every manufacturer is guaranteed to support them all and older machines from the same manufacturer may not support them either.  This means that the software may run fine on your machine but not on the computers of other people.

Here is an excerpt from the PowerVR Performance Recommendations guide.  This is the sort of thing that you will see in various documents from other GPU manufactures as well but the specific details will change slightly between them(ATI, nVdia, PowerVR, Mali, etc..) and even between different generations of cards made by the same company.

  Finally, a few additional points should be considered when using NPOT
  textures: • POT textures should be favoured over NPOT textures for the
  majority of use cases as this gives the best opportunity for the
  hardware and driver to work optimally. • A 512x128 texture will
  qualify as a POT texture, not an NPOT texture; rectangular POT
  textures are fully supported. • 2D applications (such as a browser or
  other application rendering UI elements where an NPOT texture is
  displayed with a one-to-one texel to pixel mapping) should see little
  performance loss from the use of NPOT textures other than possibly at
  upload time. • To ensure that texture upload can be optimally
  performed by the hardware, use textures where both dimensions are
  multiples of 32 pixels. • The use of NPOT textures may cause a drop in
  performance during 3D rendering. This can vary depending upon MIP-map
  levels, size of the texture, the texture’s usage and the target
  platform.

Basically, if you stick with powers of 2 then you are guaranteed multi-platform support and good performance, otherwise you may have problems when you try and work with a different machine other than the one you started on.

//------------------------------------------------------

I suppose as a metaphor, we could look at this as if textures and model data are like shipping containers used to transport goods on boats, trains and highways.
If all the containers are the same, then everyone involved knows what to expect, and what to do when they encounter a container that must be shipped.

All the cranes will be able to grab it, and the container will fit into the same slot as all the rest.

If the container is different then the rest of them then there will likely be problems since none of the equipment was designed to deal with this different format and none of the people involved were trained to deal with that situation.

Update:
Here something that was recently posted on the Blender Bug Tracker.


Unlink physics of duplicated objects in Blender Game

I don't think it's possible without a cumbersome LibLoad setup.

But you can use separate collision objects as a workaround.

Code

# Assumes the visual mesh is no-collision and the collision mesh holds logic
ob.replaceMesh('visualobject')
ob['collision'].endObject()
ob['collision'] = scene.addObject('collisionobject', ob)
ob.setParent(ob['collision'])

Example blend


Dashed Object attached to primary object

This is a texture space coordinates, that can be  enabled accidentally by pressing Shift+T

You can disable it from display in Object properties on display panel:


Export animation from blender to a threes.js program

There are two things here:

you need help with three.js exporter addon and
the thing you are trying to export isn't supported.

The current Three.js exporter will export certain types of animation, but  an animation where the Boolean modifier is of prime importance (modifying the mesh every frame) isn't going to work as you hoped. For that to work Three.js would need to have a way to deal with the boolean operation, and it would need to be analogous to Blender's Boolean modifier. To my knowledge Three.js has no such feature.

The exporter by MrDoob and associates strips out modifiers by applying them if possible. The boolean modifier can't really be applied per frame unless you export the mesh (per frame) to a format that Three.js knows how to handle (per frame). But that turns into a different question, that you might want to ask on github issue tracker of Three.js


When I Parent my rig, it will offset my model. Why?

I found the answer, you have to parent the bvh file to the model in Rest Position.


Several things matter:

The vertex count must be the same. = (v0...v19)
The edge list must have the same vertex indices to build each edge. That is, the same vertices must be connected. = [[v0,v1],...[v10,v11],[v18,v19]]
The polygon list must have the same vertex indices to build each face. That is, each face must be formed by the same vertices, in the same order. = [[v14,v15,v7,v4],...[v7,v6,v18,v19]]

Basically, you can move the vertices all you like, but you can't change how they connect.

Here is an image to demonstrate a deformation:


About BVH:

BVH creation is a method of space-partitioning to speed-up ray-tracing (or also collision detection, etc.). BVH itself is a node-tree data structure that wraps polygons in bounding-boxes based on spatial-hierarchy - thus Bounding Volume Hierarchy. You can compare how BVH looks (left) in contrast with Octree (right):

Space data structures eliminates potential ray intersection candidates by omitting geometric objects in bounding volumes which are not intersected by the current ray. It's still an area of active research (gpu friendly implementations) - there are many more types (kD-tree, BVH, BIH, Octree, Uniform Grid,..) and it often depends on what you need them for.

Here is link (.pdf) for more reading how BVH works for anyone interested.

Now static vs. dynamic option for view-port:

If you start view-port rendering BVH will be created. When the scene is changed (this counts object movement, geometry deforming, etc.) the static BVH needs to be completely rebuilded resulting in slower update times. But it renders faster. With dynamic BVH only a portion needs to be updated, which results in faster updating but it renders slower.

For rendering only static BVH is used, and the BVH tree can be also cached for faster re-renders (when for example only camera or materials changes) or cached for all animation frames for faster re-animations (if that's a word:)


How to make F12 invoke a render tab and not open a new window?

If you go to:

Edit > Preferences > Interface,

under the Editors drop down there is another drop down called Temporary Windows. If you open this drop down, you will see a setting for Render in. If you change this to image editor, instead of it opening a new window it will change your editor type to image editor.


Is this face topology good for animation?

You should avoid tris and ngons in your geometry, even if its a game model (its ok for mobile game models though - depends on polycount)

The meshflow is ok, its not good around the nostrils. Here is a good edgeflow that I recommend, its from a Zbrush course:

 Source: Zbrush workshop with Ryan Kingslien
 Direct Source: Workshops with Ryan Kingslien
 Probably the Anatomy Of The Face (no guarantee)

You will know when you are ready for professional level, someone will just employ you. There are different levels among professionals too. Just practice and your confidence level will increase. You are basically ready when you know what you are doing.


Rendering a video sequence does not Display

If you go under the render tab, go down under post-processing and un-check the compositing pipeline and select the sequencing pipeline. Then try.


I've gotten about 3/4 of the way there on this. I can move in every axis. However, you have to hold shift to Pan. While panning, you can't orbit. It's quite frustrating, but it's better than nothing, I suppose. Do the following:

Reverse all axes and crank them up to max in the 3DConnexion software.

I have the following settings in Blender:


How to keep gizmos visible when moving objects?

You cropped the solution out of the posted image. Use the move tool.

Or you can enable the move tool overlay:


How to rename all text objects by individual text content?

import bpy

for ob in bpy.data.objects:
    if ob.type == 'FONT':
        ob.name = ob.data.body[:10]


I think I've found. The menu is called "Get from object" in "curve" menu. This displays the "spline from object" node....
Anyway, the final result is not working for me. If someone can help me with a tuto, I could appreciate.
I edit:
The problem is fixed:

First, the "combine mesh data" node is "combine mesh" now.
Second, in the "Mesh Data Output"node, if you look for the "target" object, you'll not find it. You have to click on the "+" icon.
Last, in the "Mesh Data Output" node again, don't forget to click on the button that becomes blue in front of "MeshData". And it works.


Can't import characters and animations from mixamo

The Fbx is ok, but the mesh is controlled by its armature, so if you want to rotate it you have to rotate the armature, not the object.


Cycles: image rendered with zero light, why pixel value is 11 instead of 0?

It can be hard to spot, if you don't know, but Blender's factory settings give the World a default color of (0.051,0.051,0.051), with an emissive strength of 1.
So you're right: there is "Somehow, another source of light" in your scene.


Is it possible to lock the scale when entering dimensions?

There are two alternatives:

Scale your object in Object Mode as you describe, and then Apply the scale (Ctrl+A). Your object will then have the correct dimensions and the scale will be reset to 1,1,1

As an alternative create your object and do all of the scaling in Edit Mode, that will not affect the scale of the object.


Try unchecking the Use Subsurf Modifier in the Unwrap popup.


Keep part of mesh square when applying subdivision surface

Subsurf is very dependent on how your topology flows. When you see an ugly pole that pinches your geometry that's when you got to rethink the topology. Poles are not evil but they are unavoidable as they control the flow of your topology but must be used sparingly, specially in organic or semi-organic surfaces. The pole in your geometry doesn't look right:

I would suggest changing the topology so you get better subdivision. The red lines control the flow and the blue lines reinforce the geometry to crease the edges:

Make sure to clean up triangles; you want all quads when possible.


It looks to me like you are suffering from a lack of anti-aliasing.

If you are using cycles, you'll need more than one sample (Properties > Render > Sampling) in order to get good anti-aliasing. Try maybe 15 or so, and increase until the result is smooth enough for your liking.
Keep an eye on the rendertime though.

If your animation consists entirely of flat colors, I would recommend using BI or
OpenGL render instead.

OpenGL

The OpenGL render operates using the same techniques for the viewport and realtime games. In other words, it renders nearly instantaneously (especially for flat colors).

To enable anti-aliasing when using OpenGL render, enable Anti-Aliasing in Info > Render > OpenGL options and choose a suitable number of AA samples (more == slower but smoother):

Blender Internal

If you need a little more than just flat colors (motion blur, for instance), then you might consider BI. While perhaps slower than OpenGL (depending on your hardware), it's still much faster than Cycles when it comes to flat shading:


Apparently there needs to be a "config" folder with the appropriate files inside the version folder of a locally extracted blender version (e.g. C:\BlenderTest\blender-2.80.0-git.c0c1b4542f39-windows64/2.80/) for it to ignore USER and SYSTEM settings.

Creating this folder and copying over the appropriate files "userpref.blend" and optionally "bookmarks.txt" and "recent-files.txt" isolates the respective blender.exe from the user and system settings. Any changes made from this executable are saved in the local userpref file.

See this answer for file paths under common operating systems.


How do I resize an armature without ruining its poses?

You will have to scale the pose data's F-curves (you don't need to scale the armature and apply the scale then..):

You need to have keys for scale and location for every bone
Hide rotation f-curves for every bone (don't want to alter rotations)
Set pivot to 2D Cursor and position the cursor so the Y is 0 and X is any frame:

Select all visible (A). S+Y to scale animations/poses in pose space. Tadaa!


What is this Shape Key Icon referencing?

The icon shows that there are shapekeys on that object. The name is normally set to Key with a number suffix if that is already in use, but can be renamed.

In the outliner you can double click the name to change it.

From python you can use bpy.data.shape_keys["Hide.001"].name = "NewName"


You could save the file into the site-packages directory, which is found by going to your Blender folder and then 2.70 > python > lib > python3.3 > site-packages.

Say your file is called "Foo.py" and has in it a function

def X(p,q):
    return p + q

then, after saving it into site-packages, in the Blender text editor or console, you could use:

from Foo import X


Create two rigid body armatures, one with animations, and one without animations. Constrain the bones of the rag doll to the rigid objects. switch between the both of them at the moment you want to let it fall. You should probably create a python script where you copy the location and orientation of the animated armature to the rigid objects. After that you just set the animated armature to invisible, and the other to visible.


Even with all bone transformations cleared, as soon as my rig is in pose mode, it distorts my model

A possible solution to a similar issue I had was that I had left over vertex groups from parented to the metarig and it deformed the character after I parented it to the created rig. I had to delete all the non DEF vertex groups (associated with the bones, not other vertex groups that I created).


Back yourself up against unintended side-effects, and hit CtrlA > Clear Transform Menu > Clear Location. This will land your object's origin on the curve.


How do you add multiple colors to one object

Oh! Good question! This is so easy, that it should probably be used a lot more than it is on objects.

I assume you know how to create the color materials for objects, so I won't address that. Every time you go to the materials tab to make a new material, you click the "+" or "Add" button. You can do that many times. So, go ahead and create the materials you need.

BTW, the method I describe here is SO simple, but, the best way is to absolutely UV edit. Whew! What a chore. I prefer this stupid simple method.

What you do next is simply go into "Edit Object" mode, and use the "face" selection. Select the faces you want of the particular material. Select the proper material from the list of materials I advised you to create above, and click that "Assign" button. Select the faces you want of a different material, and, from that same list of materials, "Assign" the appropriate material to those faces. Stupid simple, no?


Why is my characters hand spinning in a circle?

This is a very common error/mistake in the animation part of the blender. I am pretty sure that you have a keyframe with a value like '24' right next to another keyframe with a value of '384' (or some values like that). The keyframes are so close to each other and so different, that when they are played, they make the hand move super fast that way.
To fix this, I would delete the keyframes and remake them with smaller values.


How to enable or disable panels with the click of a button

It's a panels poll method
The panels are defined and sitting there polling away, waiting to "show".
The poll classmethod of a panel returns true only when the required context (or otherwise related) conditions are met
Poll method for custom panel
Hide Panel With Python ("A Duality Duplicate")
In example displayed in question :
(Speculating haven't checked (...lately), Turn on Developer Extras in settings, so can right click on 99% of UI, view source and see how its done... a common practice is to)
Have one master materials panel, that always polls.  In this case the material slots, no panel header, has the option to add a material.
All the others seen are , subpanels ie Panels with their parent set to the master panel, or others in the space, that have poll requirements met.
In the properties space, there is a sort of "polling" option available by setting bl_context of the panel class to match that of the properties space context, matching the 'OBJECT', 'SCENE', 'RENDER' tabs.
Creating new tabs in properties panel
How do I add a panel to Object Properties?
These subpanels only poll when there is a context.material (In properties space there is a material context member, most likely context.material == context.object.active_material
When all the panels require the same poll it is common to see a mixin base class
class SomePanelBase:
    bl_context = 'MATERIAL'
    @classmethod
    def poll(cls, context):
        return context.material is not None

And for any defined panel
class MaterialFooPanel(SomePanelBase, bpy.types.Panel):
    ...

making any such defined panels only display if there is an active material.


I saw this video a while ago that provides some fixes: https://www.youtube.com/watch?v=2O0QcLpAxV4&t=545s

Basically:

If you have a planar object, like a plane, it is bugged. In the flow object panel you have to increase the surface thickness from 0.5-1.
Make sure both object fluid modifiers, the domain one and the flow one, aren't hidden in the viewport or on the render when you bake fluid.
Make the Flow object bigger, but not bigger than the domain object and the flow object must be inside the domain object.

Those are some common problems, but without the file, I can't check what's wrong. Hope my answer helps, though!


Repeated subdivides are not in single direction

Hmm. I did some testing. That video tutorial is from 2013 so the creater of that tutorial must have most likely been using blender 2.61 or 2.62 or 2.63 as that was the latest at that point of time.

When I downloaded and ran blender 2.61 the subdivide behaved like it did in the video. So this implies that something changed in blender since 2013. Since 2013 a lot has changed.

The subdivide behaviour you get now is the correct behaviour as per the latest blender. The older blender subdivided in one direction.

I would advice you use edge loops like suggested by  Dontwalk earlier i.e. with Ctrl + R shortcut to slice in one direction.

Alternatively download and use blender 2.61/2.62/2.63 to follow along with that tutorial.

Older versions of blender can be obtained here https://download.blender.org/release/. The date of release of those blender versions is also mentioned there. (Note: these versions are no longer supported -- use at own risk).


As far as i know, it is not possible, you have to do a manual retopo or use a decimate modifier to reduce the polycount.


Is it possible to edit bone positions on the posed (not rest) stance?

If I understand correctly, you want to change your rest pose, but permanently, so that when you go into Edit Mode, the bone positions do not revert to any other position, because they've been truly changed from the position they were in originally, making the new position the new default rest pose, even in Edit Mode. There is a way to do this, and it's not difficult, but the steps are somewhat counter-intutive.
With your desired pose in place, go to Object Mode and select your character mesh. Go to the Modifiers tab in the Properties Panel, and locate your existing Armature modifier. Duplicate it. You may notice that the mesh jumps, but don't worry. For the moment, it's having the tweaks it's receiving from armature modifiers doubled because there are now two of them. Thankfully, this will be a very short-lived issue.
The next thing you want to do is apply the instance of these armature modifiers which is higher in the stack, and keep the other one.
Now go into Pose Mode and select all your bones. Press Ctrl + a and then from the Apply menu, select Apply Pose as Rest Pose.
You're done. When you go into Edit Mode, you will see that the armature really is in the new pose.
Hope this helps.