0
$\begingroup$

enter image description here

Hey guys, so I am trying to model this shoe, but while baking the AO texture, while I am supposed to get decent AO shadows, I am getting this black patchy shadows all over the botton shoe model, how do I make it so it renders properly without this, I have edge sharps all over the bottom mesh, could that be contributing towards the problem??? enter image description here

enter image description here

enter image description here (Node tree to bake the AO map, I used the Diffuse method for baking it on a blank image file)

Any help to solve this will be appreciated!

Thanks in Advance!

https://drive.google.com/file/d/1qIC3FULVsymfDdh55_6ejYJptfjIXkPE/view?usp=sharing

$\endgroup$
8
  • $\begingroup$ might be that the resolution of the texture is too small, or might have to do with the UV island being too close to another UV island $\endgroup$ Commented Jun 14, 2023 at 14:27
  • $\begingroup$ Actually before baking the AO map ( I use the diffuse baking method with a node tree that I will share, it shows the node tree's AO material properly, only gives me issue when I try to bake it, also I am not able to upload the blend file, because it's over 100 mb $\endgroup$ Commented Jun 14, 2023 at 14:30
  • 2
    $\begingroup$ I think it makes sense that it only becomes an issue after baking. Before baking, the AO node has nothing to do with texture resolution or UV map. But when baking, you're baking the result of the AO into a texture that has a resolution, using the UVs. So if the texture resolution is to low or the UVs are not good, issues will arise after baking, not before. $\endgroup$ Commented Jun 14, 2023 at 20:02
  • 1
    $\begingroup$ I tried a 2K resolution, so it works now $\endgroup$ Commented Jun 15, 2023 at 7:09
  • 1
    $\begingroup$ Hi, @AtharvaDeodhar, all... could someone post a brief answer to this, to mark it as solved? $\endgroup$
    – Robin Betts
    Commented Jun 15, 2023 at 7:54

1 Answer 1

2
$\begingroup$

When you have intersecting meshes, you're going to have discontinuous AO. When you use an image texture to represent that AO, you're limited to discrete samples of that AO, spread across the face. And so you'll have bleed, including bleed across any discontinuities that exist.

Let's apply modifiers to see what we're dealing with. Think about this face:

enter image description here

What is the AO on the bottom edge of that face? Probably, close to 1.0, no ambient occlusion, because of the slight angle to the next surface. But what is the AO on the top edge of that face? It is completely occluded, black, 0.0, because it lies inside of the mesh with which it intersects.

Meanwhile, how big are our texels? With a 1024^2 texture, we can see that they are very large, and that the entire line of intersection is going to include area both inside (fully occluded) and outside (barely occluded) in individual texels:

enter image description here

Of course, we can increase the size of that texture; if we use a 2048^2 texture, then each texel will become a quarter of the size they were before. This will reduce the size of any artifacts and so improve the AO. We could increase the texture size further. However, we're not getting rid of the artifacts; we're just making them smaller.

And there's something else worth worrying about here, which is texture filtering. When we use texture filtering on lookups from this image, we'll find that as we zoom out, the texture will get darker, as more and more fully occluded texels blur further and further onto the visible part of the mesh. (And unfortunately, not using texture filtering is not really an option-- it's important to prevent other artifacts.)

Is there anything we could do that wouldn't just minimize the artifacts? Yes, we could make meshes that didn't intersect. We could do this with boolean operations, or we could retopo to a single, manifold mesh. If there is no mesh intersection, then there is no discontinuity in AO-- there will be no black to bleed out.

$\endgroup$
1
  • 1
    $\begingroup$ Hehe.. if not a brief answer, then maybe even a proper answer :D $\endgroup$
    – Robin Betts
    Commented Jun 15, 2023 at 15:42

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .