Cycles Artifacts

[Chic Aeon]

I can't figure out what is wrong here . Simple buckle made from a cube with subsurf and some edge loops removed (same issue before removing those loops).  I have odd artifacts that I haven't seen before when I go into render mode. My set up is the same as it has been. It has nothing to do with the texture. The artifacts show up even with NO texture use (that is black marks on hot pink).  There is no extra hidden geometry that might be causing an issue.

 

I have made smaller items (earrings) with no issues and it seems like this should be similar.

 

No issues in the belt leather portion.

 

Ah, I did think of one thing but not sure if it is important. This file incorporates an armature for fitted mesh. I used the fitted-mesh270 file from here http://blog.machinimatrix.org/fitted_mesh_survival_kit/

 

Hints appreciated. Maybe it is just too early in my morning and I am being exspecially dense :D.

 

[Drongle McMahon]

The only way I have found to mimic anything remotely like this is by having two copies of the object, one with the material and one without. Even then, to get the artefacts following the edges, it requires both to have a subdivision modifier with different levels on each. Without that there are different, triangle-shaped artefacts. Any chance you have an accidentally duplicated copy (object or edit mode)?

[Chic Aeon]

I agree that is what it looks like . But alas that isn't it; I had checked that. I went back again and rechecked. If I had the buckle that I see there is no other buckle even on other layers. I must have hit an odd keystoke combo somewhere along the way.    Sometimes starting over is the fastest way end game. Thanks.

 

Hopefully I won't see this again

 

EDIT: I exported the buckly only to a new file and put the same node set up on there with the same texture (sure that isn't it) and got the same issue. So something is wrong with that *&^%^& buckle **wink**.   Have NO clue what though. Happily it won't be difficult to make again and hopefully it will work this time.

 

[Chic Aeon]

Well damn . I made a new buckle within the same file. Same issue, not the exact same markings. I am thinking it is the file I started with?  Odd that it didn't bother the belt LEATHER though. I can do a work around but would be good to know what this issue is.

[Drongle McMahon]

That sounds very odd. I can't reproduce your problem at all. How did you make the buckle? What modifiers do you have? Did you use the edge split toll at all? Have you remover doubles and/or checked the vertex count against what it looks like?

ETA - also, did you render with the old Blender renderer instead, to see if that gave the same effects?

[Chic Aeon]

Yes, agreed very VERY odd.

 

The buckle was super simple.

Cube resized to thinner buckle-like shape. Some edge loops top and bottom and sides --  and deleted the middle square face on both sides of cube. Filled in the "new" soon to be edges with faces. Used SubSurf modifier at 2 - added four more edge loops to define the inside square, applied modifier. Deleted quite a few of the loops (note that I did test and it looked bad before deleting extra edgeloops so that isn't it). 

Mapped using project from view.

I have no idea how to get back to a Blender Render when I have already set the node system up in cycles, but I CAN bake an ambient map from the BAD BAD file with no issues. I get NO error messages anywhere along the way, just those odd artifacts.

 

What I DID do was make over that same buckle in an NEW file, starting it out as Cycles Render. Went through the exact same steps (they were getting etched in my memory by now) and used the same texture, node set up and even the same lighting set up. It worked perfectly LIKE IT SHOULD.

 

Since I know almost nothing about making clothes in Blender and armetures and such I can only guess there is something in that blend file I was using (a tutorial thing) that is making this problem.

I am happy to send you the very messy file from hell if you want to look at it LOL.    What seems so odd is that I also used a subsurf on the belt leather and it has no issues. It isn't like I was modeling the Mona Lisa here *wink*.

There were no doubles to remove and no edge split modifer used. 

 

I am going to see if I can IMPORT the good buckle into that problematic file and if it still looks OK.

 

Ten minutes later: Imported the "perfect" buckle into the existing BAD file, put the same node pattern on and those artifacts show up again. It is something IN THAT FILE (that no doubt I didn't do but also don't know what it is so can't fix it LOL).

 So I have a good bake that can in theory go on the buckle in the bad file. THAT is not how I like to work around things though .   

 

 

 

[Drongle McMahon]

Followed your method and ended up with very similar looking UV map, but I still couldn't get the artefact whatever I tried. I'll have to give up on that one.

[Chic Aeon]

As far as I can tell -- as noted above -- there is something in the BLEND file that I used as a basis for the build (following a tutorial) that is the culprit. I have warned others who might try adding to the file that they may end up with ISSSSSUUUUUUEEEEESSSSS  .

 

TY for trying.

[Chic Aeon]

Adding more info on this.

 

First, I did get a "good buckle" by starting over in a cycles render file and then importing THAT dae into the file I had been using for the skit and belt.

 

EDIT: I forgot to say that when I imported the 'perfect' cycles rendered buckle INTO the file originally made in Blender Render that the artifacts appeared again. It didn't matter though as I then had a good texture bake that I could use.

 

SECOND, I had a very similar issue today. What these two instances had in common is that both of the original modeling (and saving) had been done in Blender Render, not cycles.  I have had issues trying to update older files before, but not this exact issue.

 

I am still not sure WHY this happens but both of these items had sub surf modifiers on them and I don't use those all that often -- hence perhaps why I haven't seen THIS issue before.

 

SO, it may simply be that some things don't convert well from Blender Render files to Blender Cycles files. In this toolbelt there is no way I will make it over (took for-e-ver originally but I do love it). So I will have to "fix" using graphics software. Happily so far it only seems to be on the underside of the pouch. See the red star.

 

EDIT: On VERY close inspection there appear to be VERY fine lines thoughout the model. Whether these will show up on a final render I don't know yet.

 

And a LATER Edit still:  Happily those artifacts that I can see in the toolbelt didn't show up in the render (I used 250 sampling). So perhaps it is just a visual thing (I didn't actually try uploading that buckle as it looked REALLY BAD.   I will say though that cycles seems to do a very bad job with "inside edges" where there is no margin to be set. I have seen this is lots of work coming in to blog too, so it must be a common problem. I fix in my graphics program, but if there is a setting somewhere that would be great to know.

 

I have REALLY LEARNED A LOT TODAY (July 7).   Not just things discussed here. So I will keep plugging away and see if I can get a stellar toolbelt. It definitely isn't there yet . 

 

 

 

[Chic Aeon]

OK one more addition to this thread.

 

With two similar files with the same issue (both with sub surf mofifier which I don't use that often) I did one more test on a coffee cup.

It was originally a Blender Render file. I appended the same leather material to the coffee cup and made "leather" the designated material.

 

The SAME issues showed up (not as badly as the belet example but pretty much like the tool belt). AND I tested how the sampling preview setting affected the artifacts and the HIGHER the sampling the more they show up. So this seems to be a quirky little bug that doesn't matter once you KNOW it is simply a quirky little bug.

 

It certainly could affect more than subsurf modifiers. Some folks on another forum have had problems with cycles and solidify.  I seldom use that.

 

Anyway that is my report. Hopefully we are all smarter now.