OcDS 2.1 PR5 - VRAM usage, material nodes.

[DrHemulen]

I'm having a strange issue with VRAM usage. I've been experiencing sluggish interaction, so I tried to cut down on the scene a bit, and it seems like there's a lot of gemoetry that's not in the scene taking up memory:



At this point I just have G2 and a camera in the scene, but Octane seems to thing something else is going on!?

[DrHemulen]

This is with the redspex shader, and at this point it seems that this is what makes it go crazy. I have no idea why, as it's not using displacement or anything!?

[DrHemulen]

Worked some more with it. It seems the VRAM usage goes up as a function of materials. WIth Redspex, there's a material for each DAZ material, and each have 4 or 5 submaterials. Is otane supposed to use VRAM on that, even when the materials share the same textures? I can save RAM by combining say torso, hip and shoulders in one material (as they share the same map).
It also doesn't seem terribly consistant how much memory is used, which makes my think something's wrong :-/

[DrHemulen]

Eh, same behaviour in standalone, so nothing to do with OcDS.
I guess those Redspex shaders are just really memory hungry

[larsmidnatt]

I do think OcDS reports usage incorrectly at times. Sometimes restarting the program fixes it. And sometimes I think it is just assigning the blame to the wrong group. Like it will read 1.5gigs of geometry...when really it's the textures that are eating up space.

[SiliconAya]

That does seem rather over the top in terms of usage, I've never used redspec, but for comparison, a recent image I did with 6 G2F+6 Hair (hair was SubD as well) and all with different textures only used this much and my sss skin and sss hair materials are not simple in the slightest.

Also when using OcDS the number of materials and textures used in DS vs OcDS normal goes down quite a lot, not up, like in your case.

[DrHemulen]

I did some more testing, and it seems that:

1: Raw texture size checks out, these are 1/2 or 1/4 size textures.
2: VRAM use depends on the number of sub-materials in each material
3: VRAM use depends on how many materials you assign, even if they use identical textures. So having one material for torso and one for hips instead of applying the same uses more VRAM. It really seems strange but consistent. This is demonstrated, as applying the same material to several DAZ material zones lowered the RAM use.

So taken together it seems that a texture uses VRAM each time it's loaded into a slot in a given material, even if the textures are identical.

The RedSpex shaders are set up with seperate materials for EACH DAZ materials, and each is comprised of around 4 submaterials, so I think that's what's going on.

Again, this is not a plugin issue, RAM usage is exactly the same in the standalone, but it's somthing I didn't know, and something to be aware of when choosing materials. For instance, you can forget about doing much else than a single genesis figure and a simple background with the Redspecs shaders and a 2 gig card

[SiliconAya]

There shouldn't be any reason to not have materials based on texture map rather than material zone. So there should be 3, maybe 4, materials total for the skin of G/G2F: face, toros, limbs and optionally lips (if you want to make them shinier for lipstick etc.) and the only difference between those 3/4 materials should be the texture maps used, anything else will result in visible seams, which can often be visible around lips in close ups if a separate lip mat is used.

The above is for skin only, eyes, nails, eyelashes, mouth, teeth etc. all have their own requirements and depend on how much effort/detail you want to put in. Eyes alone could potentially have between 4 and 6 separate materials for example.

[DrHemulen]

Yeah I know, that's how I usually do it, but the redspecs shaders are specifically set up to have one material for each DAZ zone. The manual is very specific about this. For the eyes I can maybe see it (haha) as some of the eye components may have different properies but share a texture map.

If I rationalize them a bit they are down to about 420 megs for a GF2, which is still a lot, but not as insane.

[GrandChefPanda]

Why not ask on the redspecs forum. Perhaps you can get help from the author.