IRAY BUG? Surface invisible, but still affects character's skin in iRay.

Xameva

Hello! I'm having an issue with iRay renders. When I make certain regions of clothing completely invisible, it's still affecting the skin of my character in the final render. Please see the image examples below. The clothing item is full length gloves by Lilflame with several length options. But this issue happens with all clothing items.

The first image example is when I stopped the iRay render quickly to show iRay calculating the region that was made invisible. It should not be calculating a surface that is made invisible. The second image shows the final result (high quality iRay render settings) with the skin looking a bit muddy, if you zoom in and look closely you can see the difference of the smooth shoulder skin compared to the upper arm skin.

 Is there a fix to this?

 Thank you very much.

 

 

glaseye

It may be that setting opacity to zero is not sufficient. Other settings also have influence (glossy etc.)

Attached a small shader preset I created that I use if I do want a surface to be fully transparent. Just select the material in the surfaces tab and apply the preset...

Inluded is a tiny texture called 'black8' as I found that opacity at zero may also not work correctly when there is no opacity(texture) map attached. The shader preset will look for it in the folder

....\Runtime\Textures\!WB

so you may have to add that manually.....

Richard Haseltine

So the invisible areas have Cutout Opacity or 0? As far as I know that should be all that's needed to hide a surface. This isn't the first post saying this can be problematic that I have seen - please open a Technical Support ticket, if possible attaching an example scene, as a possible bug report.

Tobor

We covered this in another post. The Cutout Opacity block comes some time after other shader nodes, and is not involved in other nodes that contribute to the output. It is  the influence of these nodes that you are seeing. You might have some success by resetting some other nodes, such as refraction index (set to 1.0), refraction weight, glossy, etc. I recall seeing a script on Sharecg called Hide Iray Surface that might be useful in your experiments. It just zeros a bunch of stuff out.

fastbike1

I seem to remember some comments that an opacity setting of 0 could occasionally cause problems. In thoses cases, the rcommendation was a very low, but non-zero value (e.g. .001).

Tobor

the Iray uber shader does have a definition for a "null material," but I'm not sure how it's implemented. It is associated with cutout opacity. In a quick review of the file, I didn't see a clearcut indication that the geometry is actually removed when cutout is 0; in any case, cutout is in parallel with other shader nodes, so setting it to 0 is not enough to completely hide the geometry in all cases. 

I think the overall problem here is that there are some clothing assets that uses material zones to provide flexibility in their design (socks, knee stockings, full stockings, etc.), and simply dialing the opacity slider isn't going to change this if other shader nodes of the material are still active. An Iray version of the asset would need to have more involved show/hide presets, though this also means that if a user fiddles with the "show" settings, they'll be lost next time the hide/show toggle is used.

Xameva

Thanks for the replies!

None of the suggestions have made much of a difference (but thanks!), but I'm glad to see I'm not the only one experiencing this.

I've submitted a ticket, so hopefully it's looked into and fixed eventually.

Tobor: Do you have a link to the other post where this was discussed already? I'd like to read it.

Tobor

Try

http://www.daz3d.com/forums/discussion/comment/1503276/

Generally you want to zero out everything, not just reset the values. The starting Iray values have too much glossiness, for example. Be sure to try the refraction settings, as those can make an object invisible, too.

The overall problem *might* be correctable by revising the MDL script that drives the Iray Uber shader -- all of the Daz Iray shaders use it. But I think it's more realistic if any products that use the old transparency/opacity trick to show hide segments be revised to use separable scene nodes that can be hidden/shown. That's more work, of course, and some products may not be amenable to it.

Xameva

Tobor said:

Try

http://www.daz3d.com/forums/discussion/comment/1503276/

 Thanks a lot, I found at least a partial solution there! You can hide the surfaces 100% with the "Geometry Editor" tool.

theprivateco

I think I partially solved this. I was having the same problem, it is the most FRUSTRATING thing ever, and no one seemed to have an answer.

 

Switch the shader from "iray uber base" to "simplesurfacebase" in the surfaces / preset tab under shaders. This has worked for me. It seems the options for bump maps and normal maps have disappeared however. I will see if I can find them. If not, it wont be a problem for my use.

My cut out map (polka dots on a shirt) was looking PERFECT in the texture shaded view but came out looking like linen or something in the iray preview. Was the most frustrating thing ever. I zeroed out everything as recommeneded. Nothing worked. Try changing thee shader.