Why is "Retrieving Device Geometry" so slow sometimes?

jmucchiello

Why is "Retrieving Device Geometry" so slow sometimes? The scene is only 3MB compressed and contains 9 G9 figures, a couple walls, and like 5 props. (All of the hair is mesh based, no strand based hairs)

I have a 24GB 4090 and 128 GB system RAM on i9/14000. The scene uses 23GB of the VRAM. (CPU fallback is disabled.)

I am running the beta.

 

2026-05-06 21:02:17.814 Iray (Scene Access) : Retrieving geometry

2026-05-06 21:02:17.816 Iray (Scene Access) : Retrieving device geometry

2026-05-06 21:02:25.671 Iray [INFO] - IRAY:RENDER ::   1.9   IRAY   rend info : Initializing OptiX for CUDA device 0

2026-05-06 21:06:53.944 Iray (Scene Access) : Retrieving volumes

 

DrunkMonkeyProductions

In answer to your question, you've got a lot of geometry for iray to process.

Nine g9 figures alone, at default settings, is ~14,000,000 polygons at render time, just for the body.

Add in the geografts, mouth, tear, eyes, eyebrows, clothing, hair(even if it's not dforce or polymesh), the walls and props, and depending on sub-d settings, you could be looking at 20,000,000 polygons or more at render time.

All that geometry has to be processed, by the cpu, on a single core, before it's handed off to the gpu.

Thus, it can take a long time before it starts rendering.

 

Also, files size tells you nothing.

While scene, and other files, can get quite large, they don't contain all the data for the scene.

Geometry data, for instance, isn't contained in the scene file, but is contained in any DSF's, obj, etc files associated with assets used in the scene.

Instead of having all the data in the file, it just has lines of code that tell the software to load a related file.

A scene file can have a few of these "calls", or can haved dozens,hundreds, or even thousands.

The linked files can have similar calls of their own, further increasing the number of files required to load an asset.

The practical reason for not using a single file, is that if there's a problem, it's going to be near impossible to troubleshoot as you won't be able to open the file in a text editor.

It also takes up unnecessary room on the drive, with redundant data.