Displacement tag performance issues with layers

[akos_kiss]

Hi All!

We are currently running into serious performance issue with displacement tag (normal mode). we are using custom base displacement maps with UDIM mode and layering on some finer detail with 2 more displacement maps (from quixel megascans). The main displacement map is 4k the extra detail maps are also 4k.
we tried three setups:
- the built in c4d layer shader with the vraybitmap to make use of the udim s and the other two bitmaps in standard bitmaps.
- the vraylayered shader with vray bitmaps. using the base dispalcement maps in UDIM mode
- no USIMs but with c4d layer shader or vraylayered shader but the performance was also very bad

quality settings:
view dependent: on
edge lenght: 4
max subdivs: 20

i both cases the time to first pixel took really long. When we try to change any setting in the c4d layer shader, or the vr layered shader inside the displacement tag the whole ui becomes unresponsive for seconds. We have around 10 obejcts that use different dispalcement maps with this udim method.

The ui lags are also apparent when just selecting the geometry tag. it takes 10-15 seconds to load up the displacement menu.

Unfortunately i can't provide a test file at the moment because of a close deadline but any help would be highly appreciated. Maybe next week i can get back to this issue.
we are on win 10, V-Ray 6 for Cinema 4D, update 2.4 (v6.20.04 from Sep 17 2024). vray CPU mode. cinema 2024.4.1

[deyan.hadzhiev]

Hi akos_kiss, what you describe sounds quite troubling. Mostly, the part where you describe that the UI is freezing seems like the problem might not be in the actual displacement, but rather a general problem with the files (e.g. rendering previews, resolving the file names). It would really be great if you can provide us with a minimal scene reproducing the issue.

For now my suggestion is to try using absolute paths for these textures and avoid UDIMs (there are some known issues which we have planned for resolving).

[akos_kiss]

HI deyan.hadzhiev Thank you for the swift respnse. Ill disabled the previews for now. I'll switch out the relativ paths to absolute and try to change the displacement to no use UDIMS in the displacement. Some further note that the materials also use UDIMS (i disabled them to to isolate the displacement issues). But the materials work fine with a UDI setup, the VFB is a bit slow on the update, but with a tens of 4-8K texture its was expected.
I know that this is a maxon issue, bt it is really frustrating that the built in asset manager couldn't handle the UDIM textures ( this has been the case for a long time) .but the vray bitmaps work fine apart from the slowdown compared to not udim texture maps.

I'm in a bit of a rush atm, but next week i'll get back to you with a cleaned up scene file and send it over to the support!
Thanks again!

[akos_kiss]

Hi deyan.hadzhiev i just wanted to report back, that i made the scene work without udim-s and changed all paths to absolute and it made a big difference in the scene parsing time. It still has some sluggishness but for now it works. I can't really share a simplified model here on the forum but i sent it to the support with request number number: Request

[wolfgang_himmelfarb]

Wondering if you could use 2D displacement? It requires uv mapping(so no triplanar or material mapping overrides) but save on memory an imo better results.