mesh edges not aligned when exporting Closed

 From:  Michael Gibson
3869.52 In reply to 3869.51 
Hi Marc, but doesn't that render-time displacement that you're showing work on any kind of polygon model, not only one made up of just of quads?

In fact in your example there, it looks like the cylinder to the right has an n-gon cap on the top, not all quads on the top, yet you show it displaced in the rendering?

As far as I can tell, you can do "sub-polygon displacement" in Cinema4D on any kind of polygons - that means to dice any polygons up into smaller pieces before perturbing their vertices by the displacement, the "sub" in this case doesn't mean "subdivision surface" in the same way as a HyperNURBS smoothing.

Here's a quick test just to verify - here's a model that is not suitable for sub-d smoothing, it has not been retopologized into quads only, it's got just 1 big n-gon polygon on the top:

Yet it can still be rendered with a displacement maps with "sub-polygon displacement" enabled:

However, since displacement mapping works in Cinema4D by perturbing vertices around (instead of by perturbing micro polygon render samples which is a way some other renderers operate) you probably want to export such models out from MoI into more finely diced up pieces.

You can do this just at meshing time though, you don't need to retopologize your model into a subdivision surface friendly topology first, you just use the "Divide larger than" option when generating a mesh to dice big polygons up into small pieces (and you may as well just use Quads & triangles instead of n-gons), that looks like this:

Having more regularly spaced vertices like that will make more points available for the displacement mapper to push around. But note that this is just an option that you set when exporting the mesh from MoI, you don't need to totally reorganize the topology of your model for this purpose.

There are some render techniques that do combine displacement maps with subdivision surfaces as well (not sure if this applies to Cinema4D in particular though), but it is typical to be able to do displacement mapping on just regular polygon models. Just generate a diced up mesh if your renderer doesn't incorporate displacment directly into its sampling pipeline like RenderMan.

- Michael