koobas.hobune.stream
Modeling Best Practices--manifold vs non-manifold
I am having to create some models for a small project, and, though I know my way around 3D software, I am not really a 3D modeler, and I am a little unclear about what are some of the dos and don'ts are for a couple of specific points of mesh creation.
Specifically, I have read some contradictory suggestions about manifold vs non-manifold geometry and one-sided vs two-side surfaces. I appreciate that there are different trade offs for using more and less expensive solutions but I lack the prior experience to evaluate the costs, and would appreciate some input.
First of all, the project is a linear, narrative VR--Oculus and Vive, no mobile, and with minimal interactivity. It will be non-photorealistic, and not super-high detail. No more than four characters will be present at one time and the most complex character model will be around 4K triangles, most will be less.
One issue is one-sided vs two-sided meshes. I would like to use some simple cloth simulation, for a scarf and some other dangly bits of fabric. According to the Unity docs, using a two-sided mesh for cloth sim is better for performance than doubling the geometry being tracked by the cloth.
The other issue is manifold vs non-manifold geometry. I know that in general, manifold is preferable, but I have read some contradictory info about what exactly defines "manifold" as far as game engines are concerned. I know non-manifold is an absolute no-no for 3D printing, but at in at least one place, I read that simple holes are not considered non-manifold for games.
Specific questions:
#1. Are holes in the facial mesh where the eyes go a performance issue? Would it be better to close the hole with few polys, or would it not have any meaningful impact?
#2. What issues am I likely to experience using a two-sided shader for the cloth? My impression is that it will be a performance hit, shading may not work quite normally, and that there could be distance sorting issues. Are these correct impressions and are there any other issues I should be aware of? .
Thanks for your input.
