Rendering in Blender woes

Shivan Hunter · Sun Sep 23, 2012 3:39 am

So, not sure how many of you use Blender's epic rendering capabilities to make ship graphics. Anyway, since 2.49 was having issues, I recently downloaded 2.63 and tried to render a sort of alien weird station thingy I made in Wings3D (exported/imported through collada .dae). I'm having two problems with this.

First, auto smoothing on the models apparently does nothing. I set it to a threshold of 30 degrees (the default) but it still renders like a faceted model.

Secondly, the directional light looks all wonky unless I raise its number of samples from 1, and when I do, the shadow disappears.

Pics for reference.

1 sample light (note the shadow from the sphere):

2 sample light (it's grainy but Blender just does that):

6 sample light (less grainy, better light but no shadow, notice it still looks faceted):

LordSutekh · Sun Sep 23, 2012 4:05 am

It looks to me like you have duplicate faces. Blender has a hard time smoothing objects with duplicate faces which can occur when you convert formats. Try deleting a face and see if you have a duplicate underneath. That's usually the cause of jaggies. A note on auto smooth; auto smooth only works if you check auto smooth and then smooth the object. It will display smooth but render with the degree of sharpness you specified. If you still have problems with auto smooth, you can also try using a subsurface modifier.

Shivan Hunter · Sun Sep 23, 2012 4:27 am

Yeah, I never actually smoothed the object. Did that, added an edgesplit modifier, and it works excellently.

Sun Sep 23, 2012 4:28 am

We got this worked out over IRC, looks like the problems were (a) not actually having smooth faces set (got it working with smooth faces and the edgesplit modifier, since I don't even know how to make autosmooth work

), (b) blender 263's multi-sample sun light w/ adaptive QMC dosen't seem to cast shadows on other objects, it was fine when we rolled it back to single sample.

I forgot to check for duplicates .... nah, removed zero vertices in all cases, so that was never a problem.

Oh, general advice for anyone working with blender ... whenever you see shading artifacts, select the entire mesh and ctrl-N to recalc normals. Usually when I go from a profile and extrude it several times and then switch on subsurf and/or smooth shading, some part of the mesh goes wonky on me cause the normals didn't do what I expected on one of the extrudes ... and stuff like that.