Light Cache building randomly spikes when starting a render

[olika]

Hi there,

is just encountered a problem in total different scenes (big environments to simple studio setups)
when Light cache calculation kind of randomly spikes when starting a render.
Seen some posts already in here but not sure if it's the same behavior.
In my case the time spikes to 24h or more, then kind of stuck and then when it over that it kind of renders fine.
As i stated out it happens in total different scenes, so right now i have a large outdoor environmet with forest and railclone etc.
I'm trying to tracking down the problem but right now it seems kind of random, i cannot track it to itoo stuff, proxys and materials.

Playing around right now with some Light cache stuff like turn on/off retrace, leak prevention, sample number etc, but all have no effect on the problem...

Any tips on that one? Because that lag of lightcache is so annoying that the whole workspeed is almost coming to an grinding halt right now ;-(

[kosso_olli]

We get weird light cache behaviour in scenes with displacement. The light cache might hang around 10 minutes not doing any progress, and then finishes in a few seconds.

[olika]

Thanks for reply kosso_olli !
Already turned off displacment in the global settings, not getting better
right now it when i track down the scene it's NOT:
- forest objects and materials also trees as proxys (all good here, suspected some problems here)
- proxy geometry is kind of fine, slows down a little as expected
- displacement (not at all in the scene right now)
- light cache settings / embree
- heavy xref scene (little slowdown as expected)

But when i bring in some Railclone Elements Lightcache seems to start having a hard time

I will investigate deeper into railclone stuff to see if i can find some quirks there

[olika]

After further testing i found a piece of geometry which was somehow screwed (part of a roof from revit data, didn`t looked to bad but LC really didn't like it)

The scene i'm working on is again a big environment with quite some forest and railclone stuff(2 different forests, lawn, proxys and a big xref file of industrial installation coming from revit.
Right now it takes approx. 1 minute to calc the LC which i think is quite cool, let me know what you think