Proportional editing problem I'm new to blender and I have a problem that I can't solve and where the internet won't help me.
I have a column and want to make it look like it was cut. So I want that the upper vertice goes into the blue circle and that the other vertices makes a straight line to the lower vertice. I tried to use the proportional edit tool but none of the meshes  solves the problem. So is it possible to use the proportional editing but fixing a vertice and making the other vertices do a straight line between the fixe vertice and the edit one ?
Add a cube, and position it so that its lower face sits where you'd like the cylinder's vertices to be. The tip of the cylinder should be inside the cube.



Select the cylinder. In the Modifier Properties tab, on the right-hand side pannel, add a Boolean modifier. Make sure it's set to Difference and, under object, select the cube (be aware that there might be many cubes in your scene; make sure to select the right one).



Your cylinder should now bear a cut as the one you described. If evertyhing seems to be in order, hit Apply in the boolean modifier and get rid of the cube.