Ambient Occlusion settings in blender?

[Simmo W]

Hi everyone,

Anyone know what's going on with my settings in blender, that cause the unsightly large dots in this image? I'm really pleased to now be able to render an object, fiddle like crazy with settings (still don't know half the effects!) and then finally have it UV mapped to a texture file, but this is driving me crazy. I tried upping a few settings, but can't remove the less subtle black areas you see.

Any ideas? is it another setting other than AO?

Thanks

Simon

Edited October 30, 2011 by Simmo W

[Pete_SMS]

Hey Simon,

How did you create that edge where the strange shading is happening. Did you just extrude the edges of the cube and is AO switched on?

Keep in mind, that Blender 2.5X and 2.6 is using double sided polygons as a default setting (you can find that setting under object data) and I would switch that off. This also makes sense when you export your mesh to be used inside X-Plane, because it will double your poly count if you leave that on and it might create other strange artifacts.

So if that setting is on on your side and you extruded just the edges, you will have an extrusion with no weight as it is very very thin.

AO effects the surfaces based on their proximity and orientation to each other, and in this case it would be very close and the closer surfaces are, the more light will be blocked and this could result in strange surface shading.

What you could try is to remove these extruding edges and do a proper inset of that "keep right" face and try again.

I am not sure if that is causing your problem. Just thinking here.

[Simmo W]

Thanks Pete, all good points that I will investigate. Yes I just pushed that right face in a bit to create the cavity to see some AO at work. Didn't know about the double face issue, that'll save a lot of work later! Not at my pc for a day or so, I'll report back. I did find another area to improve the render quality, can't recall it right now.It largely reduced those artifacts. So many options to try

[Simmo W]

And Pete, what do you mean by a proper inset?

[Pete_SMS]

I guess you already did it properly after reading that you pushed it back in. Could have been that you "just" grabbed the outer edges and extruded them. Now, I am pretty sure that you selected the face, extruded it to the same position, scaled it down a little and then pushed it back in, right?

Have a look at this double sided polygon setting, though. That might not help you with this problem, but later for sure.

[Simmo W]

Hi Pete, I've just tried to locate the object settings, can't find anywhere to change the setting. I've looked in properties when in object mode, can't see it in object tools. Is this meant to be easy?

Stand by for another question coming through. Every time I think I've learnt more, there's more to discover!

[Pete_SMS]

Should be easy.

I will make a screenshot for you. A picture says more than a thousand words.

[Simmo W]

tx, yes it should!

OMG, I just discovered the easy Mesh/ add duplicate command! I'm gonna have lights EVERYWHERE in my sceneries!

[Pete_SMS]

There you go ....

[Simmo W]

Thanks Pete! That'll definitely help a little.

[Simmo W]

Done, found it, duh..

[tkyler]

Hey Simon..that the result of coplanar polygons, that is two faces on top of one another. The guy in the link below had the same issue. There's a couple of workarounds if you need to render bake where two faces are coplanar yet have different lighting situation on the faces. I usually separate the mesh into separate objects, temporarily delete one (or move it to another non-rendered layer) and then bake just the one part...then I do the same for the other part and finally rejoin the object, combining the two baked textures into the one final texture. As i said, a workaround but the situation isn't that common in my experience.

[Simmo W]

Another good answer Tom. This was only an early test with my very first tiny G translate, but I'm bookmarking this answer for when I need it for a real project. A great workaround.