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Set smooth - in blender - performance cost?

Posted: Mon Jul 16, 2012 10:08 pm
by chaosavy
Hey guys, wondering if the "set smooth" option in Blender (and I'm guessing other modeling software) causes a significant performance hit (if any) versus the "set solid" option.

Any info appreciated.

thanks :)

Re: Set smooth - in blender - performance cost?

Posted: Mon Jul 16, 2012 10:31 pm
by bstone
The "set solid" option requires duplicated vertices and normals so it eats more memory but performance should be equal on any modern hardware.

Re: Set smooth - in blender - performance cost?

Posted: Mon Jul 16, 2012 11:44 pm
by duststorm
If anything "set smooth" improves the speed :)
As bstone mentioned, it makes neighbour triangles share the same vertices (as opposed to flat shaded which has 3 vertices for each triangle). So the data needed for your model will decrease with smoothing applied. (and smoohing is generally what you need for 90% of your models I presume)

Don't confuse "set smooth" with subdivision modifiers, though. Those actually add extra faces (at least when you apply them to the mesh before exporting).

Re: Set smooth - in blender - performance cost?

Posted: Tue Jul 17, 2012 1:47 pm
by chaosavy
Thanks! Now I have to set smooth everything :)

Re: Set smooth - in blender - performance cost?

Posted: Tue Jul 17, 2012 7:00 pm
by duststorm
Just go for what looks best, since there really is no difference in performance. I think with blender you can also set some edges sharp and others smooth, if that is what you want.

Re: Set smooth - in blender - performance cost?

Posted: Fri Jul 20, 2012 11:09 am
by Demarii
A good page on model optimization you might find interesting.

http://dungeonhack.sourceforge.net/Model_Optimization

It also links to the Vegastrike wiki with some good practices on creating nice bevels and welds.

Re: Set smooth - in blender - performance cost?

Posted: Fri Jul 20, 2012 12:39 pm
by duststorm
Indeed very good tips.
- Checking for wrong facing faces
- Finding and fixing non-manifold vertices
- Using sharp edge modifier
- avoiding intersecting triangles

All very recommendable ;)

Re: Set smooth - in blender - performance cost?

Posted: Tue Jul 24, 2012 10:09 am
by Waruck
Has anyone testet whether the sharp-edge modifier works with the Blender2Ogre exporter?
From a quick search in the script it looks like it only checks the whole faces whether they are set to soft so i guess if this is supported in any way you have to apply the modifier to the mesh but I'm not sure this works at all.

Guess I'll but it on my to-do list for summer vacation.

Re: Set smooth - in blender - performance cost?

Posted: Tue Jul 24, 2012 10:21 am
by duststorm
Good point. I don't think I've tested it.

Re: Set smooth - in blender - performance cost?

Posted: Tue Jul 24, 2012 5:27 pm
by bstone
I believe it works because I certainly used it for some models and I don't remember any visual difference when displaying the resulting .mesh in the game.