2K vs 4K texture

[John09]

So, how does 4K vs 2K textures affect the memory and render time? I Rendered a single G8F with 4k texture (500 MB HDD space) vs 2K texture (50 MB HDD space) but the memory and render time is identical in both case (tried both full body and face closeup shot). So what is being affected by 4K the texture size?

[3Demon]

Did you increase the figure's Render SubD Level setting?

You probably experienced a 'plateau'. That is, you may not see any 1) increased resolution in the render (despite using 4K textures), or 2) decreased memory use nor a reduction in render time (despite using 2K textures).

Using the figure's Parameter Settings, you can increase the Render SubD Level beyond the default parameter limit of 2. Increasing it to 3 or 4 (beyond 4 will likely crash DS) will take better advantage of 4K textures and higher for detailed closeup renders (pores, bumps, imperfections, vellus, etc).

However, increasing the Render SubD Level beyond the default parameter limit of 2 will unfortunately significantly increase the memory usage and render time.

I advise you try the comparison again by adjusting the figure's Render SubD Level. You should see a noticeable difference...at a cost.

Tangentially, vendors provide 4K+ textures because you can make highly detailed textures smaller, but you cannot make small textures more detailed.

I'm confident in my analysis, but please correct me if I'm wrong.

[John09]

I used Render SubD level 5 (since it didn’t crash), along with the 2025 alpha version and a base G8F model (Aurore G8F with HD morph on and rendered at 8K resolution).

I’m not concerned about render time, if the texture fits in VRAM, the render duration should be roughly the same. What surprised me, however, is the total VRAM usage. A 4K texture is four times larger than a 2K texture, so I expected a noticeable increase in memory usage.

But the memory reported in the log file (Framebuffer and Wavefront) is almost identical in both cases. As far as I know, the log doesn’t include geometry and texture memory, so I checked GPU usage in Task Manager during rendering. The difference there is also minimal: about 8.1 GB for the 4K texture versus 7.9 GB for the 2K.

That’s the part I find confusing.

[Skeleton]

There are all kinds of strange oddities with Daz. So if you render close to a figure vs. far it will change. Different angles can change it. If you have the program open too long it will begin to memory leak. Some hairs are extraordinarily unoptimized that you might think shouldn't be so heavy. There are probably others that I can't think of right now as well.

Also the resolution of a texture can determine the amount of memory required. But there are 4k textures that are only 1-4 megabytes and then there are 4k textures that can get up to 25+ megabytes. the amount of megabytes the texture file actually is and not the resolution is what makes the memory requirement go up. Often 8k textures are at a minimum of 20 megabytes for one picture file. That is where you can use a lot of memory. So yeah check the actual file size. If your 2k texture is the same size on the hard drive as your 4k texture that might clear some of this up.

5 Subd is lunacy... What are you doing? loking at your model with a microscope?

[John09]

I only used 5 SubD for this testing since I was trying to see any difference.
I tried both close up head shot and full body shot with both resolutions. No hair or anything, just the bald G8F straight from the package with a single HDRI.
The camera is fixed and with 8K resolution (16:9).
4k texture is straight unaltered from the item (500 MB texture folder size). I used Image resizer to reduce only the .jpg files dimension by half (texture folder is now 50 MB).
And I restart DAZstudio everytime before doing these test to have a clean log file and memory.

[Skeleton]

Ah my bad you already said that and I glossed over it.

[John09]

No it's fine. You said some really good points. I am just confused whether I am missing something obvious.

[Skeleton]

I mean when you render at 8k that is still going to take a lot of memory either way. I mean is it possible that between having your SubD high and your Render resolution high that those things are what is costing the 8GB of RAM? Have you tried doing the exact experiment at 4k render resolution and 3 subD? Seems like to answer this question you might shift some parameters and report the results because I'm interested. Or maybe you've already done it.

[Skeleton]

Okay... I just ran a render at 4k 7.9GB with 3 Genesis 9's 2 of which are fully kitted with gear/clothes, one stand based hair, one card based hair. Rendered the exact same thing again at 8k and the ram usage on my GPU was at 9.6 GB. So in your tests what is the regular RAM usage not VRAM?

[Skeleton]

Oh whoops I forgot to say they were all at SubD 3. Also I'm using all 4k textures. My normal RAM spiked like 11GB higher on the 8k render.

[John09]

So, here are some extra test, not sure how RAM comes into this unless it's falling into CPU rendering. Idle state RAM = 14 GB

4K camera resolution + 4K texture + SubD 5 = 5.5 GB VRAM
4K camera resolution + 2K texture + SubD 5 = 5.1 GB VRAM
4K camera resolution + 4K texture + SubD 3 = 4.1 GB VRAM + 16.8 GB RAM
4K camera resolution + 2K texture + SubD 3 = 3.9 GB VRAM + 16.7 GB RAM

When you do your testing, can you just test on 1 single char (G8F preferably, G9 has higher mesh and maybe some other issues), no cloth, hair or anything just HD morph and 4K/2K textures and same camera resolution. I am curious to know if it's a DAZstudio issue or special to my devices.

[ADAM]

Not sure how much it matters but there's an option (not near computer atm) that compresses textures over a certain size. If this is set to 2k then wouldn't any texture above 2k be compressed to 2k?

[Skeleton]

For my tests the Renderer is not falling back to the CPU. Normal ram definitely plays a part on my system/setup. Like when I first load a scene especially with 4 or 5 characters in the scene My normal ram can get up over 80GB not even rendering.

If I'm going to do this test you're asking me to do it will have to be at a different date because I'm in the middle of a project in Daz.

Though I thought it might be telling that our VRAM usage is nearly identical even with the discrepancies in the scene.

[John09]

@d0gg0d If you are talking about medium and high threshold texture compression, I am testing them currently. The defaults are 512 and 1024 respectively which might be too low for these testing.

Edit: increasing these values to 5000 make no difference in VRAM usage. I suppose they only kick in when the texture doesn't fit in VRAM which isn't my case.

[ADAM]

Wasn't sure but I figured it was worth pointing out. It's something I came across in threads while researching ways to improve renders. Half of the options people never use.

[Author]

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