What Causes This Weird Render Issue With Minotaur 6 HD?

Inkubo

DAZ has really been killing it with the great sales recently. I picked up Minotaur 6 HD, my only Genesis 2 character, and the Orestes Triskele Falls HDRIs. Then by coincidence I used them together and found a strange issue I can't explain. It's as if Iray doesn't like it when some of these items get used together--even if I use the Iray Uber Shader on all the Minotaur's surfaces.

Before I describe the problem, let me note that I already uninstalled the minotaur, deleted the package, then redownloaded and reinstalled it, just to make sure there was no corruption in the original install process.

I'm using DS 4.9.3.166 Pro 64-bit edition.

Here are my steps to recreate the issue:

1. Open DS and find and double-click on the Triskele Falls 01 HDRI. 
2. Double-click on Minotaur 06 HD. 
3. Change to Iray Preview and zoom in to look at his right pectoral.

As you can see in the Minotaur 01 image, shadows reveal hard edges instead of smooth curves on his body, and there is an area on the pec where textures don't "stick." It appears as if some part of another, unsubdivided model is sticking out through his body, but there are no other objects in my scene. My first screenshot shows an Iray preview, so I've included Minotaur 02 so you can see the problem appears in an actual render, as well.

Loading a new texture doesn't help. In Minotaur 03, you can see I've applied the Asterion texture, but the buggy area is still there.

What does help is to change the figure's subdivision level. In Minotaur 04, I reduced it to 0. (The figure preset defaults to 1.) The messed up area now appears to be just a stretch mark, and it accepts textures. However, the skin shows more hard angles.

The problem area also mostly goes away if you increase the subdivision level to 2. The buggy part reduces to one triangle-shaped notch that's barely noticeable. This is shown in Minotaur 05, but here I had to add an extra spotlight to brighten the shadows enough for us to see that the texture is applied.

What boggles me is that the default subdivision level of 1 works just fine if I start DS and load the minotaur by itself or when I use other HDRIs. If the HDRI is Triskele Falls 03 (see Minotaur 06), this area of the skin looks different: instead of looking like naked, untextured faces, it looks like a patch of skin copied from somewhere else. But if the HDRI is Triskele Falls 05 (see Minotaur 07), the skin looks perfect.

I included Minotaur 08 to show that switching back to Triskele Falls 01 causes the buggy area to reappear.

Finally, I used the Surfaces pane to switch to the Iray Uber Shader for all surfaces on the Minotaur model and added Minotaur 09 and Minotaur 10 to demonstrate that using all Iray shaders doesn't help.

How is it that an HDRI preset's render settings can mess up the UV textures on a model???

Oso3D

That's the weirdest GD thing.

I keep rendering in 3DL and Iray and for some reason Iray's handling of the HD details in that and a few other areas... stinks. I can't for the life of me figure out why.

All I can figure is that it has something to do with how each engine handles meshes? Weird.

 

Oso3D

So I didn't get what you were doing with subd, and that's the answer.

Most HD morphs are only going to show properly at SubD 3, and 4 is better for closeups.

 

Inkubo

Thanks! I see I didn't mention it in my original manifesto, but I did try cranking up SubD. Higher values make the ugly spot shrink, but not go away... That particular HDRI provides a lot of light, but I just used it by chance. I'm not stuck with it. Maybe the answer is to only use the minotaur in scenes which aren't so bright.