This is an open cube, but I want it to behave like a solid cube. I want to hide the 3 “hidden” edges (pipes) from view. I want the front 9 edges to be seen. If this was a static image, that would be easy, I would just not draw the rear 3 edges.
I want to be able to animate the cube and smoothly rotate it in 90 degree increments in any direction. As it rotates, 2 previously hidden edges will come into view while 2 become hidden.
Based on my limited Blender knowledge, the best approach I can think of is to make each edge a separate object (12 in total). As the cube rotates, change the material alpha value to hide/unhide edges.
First, you don’t need to cut your object in 12 to give 12 materials to it. One object can support several materials assigned to different faces.
But you don’t need 12 materials.
You can use textures for example a gradient texture + a colorramp to delimit where starts and where stops transparency of material.
But you don’t need to learn about material and textures.
You can create a second mesh object and use it as target of a boolean modifier to make a difference operation.
Second object can be hidden at render.
As long as modifier is not applied, difference operation will adapt along animation.
Put a solid cube inside on a separate scene layer, and use that layer as a mask layer in render layer properties. That will mask everything inside and behind it.
Hi
Thanks for your advice and I know just enough about Blender to understand what you’re saying.
I can see that hiding/unhiding a length of pipe would be easy. The problem I foresee is at the inside of the corners where the pipes intersect. The inside of the smoothed pipe connections is visible. If I assign a boundary that is invisible from one direction, it will be visible from another direction. Each joint can be viewed from 3 directions and there are 8 corners, so I would need to define 24 areas plus the (easy) pipes. In addition, I would need to add a second skin at the pipe intersections to remove the visible part of the fillet at the joints. That sounds viable to me.
I have thought about putting a cube inside and I can see that works great for the flat sided pipes in the example posted. I think I would have great difficulty with round pipes. I don’t think I could fit a cube inside the pipes that would correctly handle the inside of the pipe connections. That would be beyond my level of Blender model building skill.
I also plan to change the colour of the entire pipe cube mid-way through each 90 degree rotation. I guess I will need to learn more about materials and textures to do that.
Hi
I have had a thought. Each corner will be viewed from 3 directions. From each direction, one of the three edges will be hidden.
What if I:
replicated each corner with 3 versions all overlaid in the same space as different objects,
joined each corner to its neighbour halfway along the pipe edge to make a smooth joint
unhide one version of each corner at any time.
Although there are 8 corners with 3 possible view points, I would only have to produce 5 versions (then copy paste) to cover all 24 viewpoints of all corners.
The question I have, is if the objects have doubled vertices, and only one of the 3 surfaces is visible, will this cause problems with the rendering?
I found this post on making a seamless connection between different objects, but it doesn’t address the overlaid vertices. If I connect 3 versions of each corner to a empty, then associate the straight pipes and the 8 empty with another empty, then I will have a hierarchy of objects that I can move as one, or individually. I think empties might be the way to go.
