I do not know why I get the following anomaly: the more I subsurf my model, the more it creates shadow “artifacts” on the rendered image.
Image subsurfed 4 levels:
Image subsurfed 3 levels:
Image subsurfed 2 levels:
For reference, here is the wireframe too:
It’s not the first time this happens to me. Does anybody know what could be the cause of this?
Thanks,
AnyMation
PS: Although there is an improvement after I apply the subsurf, it is still there. The problem does not show up when I do not have ray tracing activated for rendering (F10).
AnyMation
Looks like inverted normals to me. Editmode>Select All>Ctrl+N to recalculate normals outside.
RamboBaby,
Nope, it’s not. And it only shows up when I ray trace.
hmm…Ive got no idea…
what are your current render settings, and material and texture settings?.. You could be getting something there…
TO be honest, this has never happened to me…
Enlarging the images that you posted, to 400%, shows that tou may have concave quads, but I can’t tell for sure without the .blend. The quads in those areas may also be set solid where the rest of the mesh is set smooth. Are you using a CVS version? Someone has reported in the bug tracker that subsurf modifier is creating smooth and solid faces on the same mesh which is DEFINITELY capable of causing this problem (at least in areas of the mesh where you have manually connected faces). I had something similar happen about a week ago. Just select the mesh in object mode and activate the “Set Smooth” button on the links and materials tab in the edit buttons (F9). Sorry if it looks like I’m talking to you like you’re a noob, I just try to answer that way in case a noob stumbles across the problem and then finds the post via a search. But the problem is most likely concave quads. Attached image is of concave quads.
Nice “SLY” by the way.
RamboBaby,
No problem with the detailed explanation.
I uploaded the blend file to http://www.dnapixels.com/RockyFace.zip. I already tried the “set smooth”-trick previously, but that did nothing. I am not sure what the problem with concave quads can be: surely concave and convex quads are “standard” shapes? …Unless you mean when you take them to the extremes, which I can understand. But I do not think the model has many of those. (Isn’t that when Blender does not want to make a face using the F-key after selecting 4 vertices - saying that the vertices don’t make a quad).
One thing: you will notice that the model is not perfect from a topology POV, but most of the “imperfections” are there because I am trying to let the model reflect the character. However, positive feedback will always be appreciated.
Thanks.
That is what concave quads are and that IS where the problem lies. In the screenshot you can see which vertex was responsible for the shadow around his mouth. It was pushed too far back into the mesh and at a funky, upward angle. It took me about 30 minutes to correct because the computer that I loaded it on is a dinosaur with only 256 MB of RAM, else I would have corrected a few more. As it was I could hardly get the model to do anything even with subsurf disabled.
I recomend that you turn off select behind mode as it makes it very difficult to work on complex meshes. I don’t understand why anyone ever thought that was a good idea anyway. I can’t stand it. That mode is probably the reason why these verts are out of place.
Here’s a link to the file so you at least have one fewer vertex to correct. I added a suffix to it’s name so it won’t be able to overwrite your original.
http://uploader.polorix.net//files/89/RockyFace2.blend
As far as crits go, I don’t have any. This is definitely the coolest Blender project that I’ve ever seen.
Thanks for your feedback RamboBaby - and your “coolest Blender project” remark, but maybe it is because you have vested interests due to your name alias :).
BTW, I am not convinced that you’ve hit the cause of the problem. If you study the details between my and your rendering, I only notice that the dark area slightly shifted due to your moving the vertex.
Two other tests I did since then also confirms that it is not the cause of the problem:
So, I think we are still at square 1…
Not that I disregard your input, I wish a Blender render guru would give some feedback on this issue.
Sorry, no guru here at the keyboard, but I think it maybe related to the infamous “Phong interpolated normals” Problem.
It’s definitely caused by the shadows, and maybe some kind of buffer overrun.
It’s definitely fixed in version 2.43, so I would consider it a bug.
The image below is rendered with Subsurf Level 4 and Version 2.43 (I’ve simply rendered your file without changing anything).
Regards
If you do a soild face render with no subsurf you’ll see that it’s still there, but if you keep pulling it forward along it’s global Y axis along with two of the other verts connected to it, you can see that it completely disappears. Now when you look at the wireframe you’ll see that the quad actiually looks like a quad. B4 you had something that was more akin to the 3rd image which is only 2 faces, but I dare you to try and tell Blender that. You can only push to a certain limit B4 normals bagin to warp or curl or whatever it is they do when you’re trying to define two perpendicular planes with only one surface area and thus one normal. These are tris with no edge to define them. Sorry if that isn’t the answer that you were looking for but it’s the one that works here. It’s just like warfare where you are not paid for your methods, you are paid for your results. Methods can get you killed at the end of the day while results will bring you back home to mama with a smile on your face.
Oh, it has nothing to do with my name. The name used to really piss me off, that’s probably why it stuck. It was even worse when they started calling me RamBone. I just think your model has more character than any other I’ve ever seen.
It doesn’t take a render guru to figure this one out. Drop your file in the modeling forum and see what comes up.
SoylentGreen: You make my day! (As I type these words, it makes me think of a model that a colleague of mine is working on the same project, but of another caricature who is renowned for similar words 
- at http://blenderartists.org/forum/showthread.php?t=85787).
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I also now did a quick render and agree with you. Phew! And thanks!
RamboBaby: I do not disagree with your point - I am the first one to admit that there some of those in my model - as I pointed out in my previous posting. These errors occur because I model directly in subsurfed mode - and in the process sometimes pull some of the vertices too far. It is a combination of relief of the model and the detail/“resolution” of the mesh. But after SoylentGreen’s input (and my tests with Yafray), I think that there is definitely something wrong with Blender 2.42a’s renderer that is the primary cause of all the shadows. Thanks for your input too!
I’ll sleep better tonight!
What are you guys going to use these models for anyway? This looks like a really cool project.
We are working on a showreel and we want to create a 2-3 minute short for it that will cause a big WOW! whenever it is seen. We are therefore putting a lot of effort into this to produce something that is of professional quality. At the same time it will enlarge our understanding of Blender. We will go the full hog: lip sync, facial expressions, music and all. I want to demonstrate the use of green screen to viewers as well, but I am not sure whether it will be in this animated story.
