Animate an emission object appearing and disappearing I am trying to make a stationary emission object (placed in between two other objects) appear and disappear to create the illusion of a flare that comes on and shuts off quickly. The emission object is 2D text and a copy of 3D text on top. The emission object has two nodes: emission and transparency connected to a mix shader. When I manipulate the 'factor' in the mix shader, the emission object appears and disappears like it is supposed to. However, when I hover the cursor over the factor entry box and press 'I' to create a keyframe it does not turn yellow to indicate it has taken and no keyframe is created. I get the same result when I hover and press 'I' in the materials tab in the properties area on the right. What am I missing?! (By way of disclosure, I'm a relative newbie to Blender and animation in general.)
You can key the visibility of the object by hovering in the outliner over the render restrict symbol (camera symbol) next to your object and pressing I to add a keyframe. Then create a invisible key on the first frame, a visible key on the second key and again a visible on the third. That should give you the flash effect you want when you render it, but it will only show in viewport if you also key the viewport visibility (but I am currently not sure if that's also possible...)