Strange issue - Where it comes from?


I’m very new to 3D modelling. :smiley:

My interest in this world started as I discovered three.js. I made a simple HTML5 model viewer using that library.

I made my very first model for that using Blender.

So I’m not sure my issue is a modelling or a programming issue. The issue is only present if I load my homemade model into it. If I use another one, it disappears so I think, it is caused by my model and not by the viewer I made.

I did following in Blender:

  1. I’ve created a big UV-sphere
  2. I’ve created another, small one
  3. I used the smaller one to cut out a piece out of the bigger one so it has a dent. I used the boolean modifier for that.
  4. I removed the smaller sphere so the big one is left.
  5. Exported everything as Collada

Then I loaded the resulting Collada file into my viewer.

The sphere looks great so far… But dent isn’t round anymore. It is out of shape and looks “buggy”. It looks like some vertices are simply skipped during rendering.

It always happens where I use the boolean modifier to cut out something.

If I reimport the Collada file into blender, everything looks great so the file isn’t corrupt.

Even everything is just for fun… What might cause this? Is something wrong with my model or is it a three.js-bug? Or some kind of optimization routine that tries to reduce the number of vertices? :mad:

Being able to see it might help. but from your description, I assume your boolean process has created a number of ngons that your HTML viewer doesnt know how to render. if you make your model with nice clean topology (tris and quads only) it should be fine.

To convert to tris and quads, apply the modifier if you haven’t already, go into edit mode (TAB), select all (A), convert to tris (CTRL-T) and then convert to quads (ALT-J)