Good ol' "unloading geometry"

[stayinwonderland]

Right, need to get on top of this before it destroys me.

 

Been making a scene and I noticed that by adding several displacement maps in the material editor, my render time turned into days, not hours. So I just got rid and settled for bumps.

 

Then I was down to two displacements, one a procedural on a bit of terrain, the other a bitmap (2048x2048) on a small plane of water.

 

Low quality renders were taking about 20 minutes at 1100px wide. Just set it to high quality (high in irradiance map, 50/20 hsph, 1500 light cache, DMC 2/8, 1300px wide) and it's taken 18 hours so far and is estimated to take another 13 for the 4th and final pass.

 

That's just not cricket if you ask me.

 

I have a hyperthread quad core i7 + 8gb.

 

Scene looks like this:

 

[ATTACH=CONFIG]46840[/ATTACH]

 

Got fog gizmo in there too.

 

Any advice? Is this a normal time for such a scene and hardware set up? Would you settle for such a render time or is vray laughing at me?

[AubreyM]

Have you bumped up your dynamic memory limit more than the 400mb default?

[stayinwonderland]

Can't say that I have Aubrey, where would I do that, and would you say it's a decent remedy?

 

Presently my cpu useage is very minimal while it's doing this. Ram is up but not maxed by any means.

[AubreyM]

Settings tab under vray system. set it to 4096 or something and try another render. it should help with the unloading geometry message.

[stayinwonderland]

Great, I shall try that when this damn render eventually completes... one last question... is this about ram and if so, I have 8 currently, but will getting another 8 help? Thus far I haven't found any tasks that really require more than 8. Thanks for the help.

[AubreyM]

Yes another 8 gig would help. Small scenes won't stress the ram but get some with a high poly count will behave a little better.

And yes the dynamic memory limit refers to the ram. If I remember correctly (someone correct me if I'm wrong) when rendering if the system hits the dynamic memory limit it will start to page the excess to the HD causing the unloading geometry message and increasing the render times.

I talked to a pal of mine that owns a computer store, he says ram is real cheap right now so I would recommend another 8 gig stick. There may be many times that you don't need it but when you do you will be glad you have it.

[matthewgriswold]

Settings tab under vray system. set it to 4096 or something and try another render. it should help with the unloading geometry message.

 

Heck, if you're hitting render and walking away from your machine I wouldn't hesitate to set the limit to 3/4+ of your system memory. What else does your system need it for?

 

System Page Files are the worst. They're a slow and cumbersome way of using memory-unless you've got a great solid state with high RPMs.

[RyderSK]

My suggestion is to stay away from material displacement, always try to go for Vray displacement on actual geometry, and 2D. The amount of ram consumption difference is enormous. Results are also easier to predict.

 

Procedural displacement by a rule needs 3D displacement, this is heavy. So for now you are using 2 render displacement at same time, I think this is what causes the problem. If you really need both ( I guess you combine small and big waves ?) then either : One baked into geometry (big ones) using displacement modifier on rather rough mesh, second using vray displacement placed after on modifier stack.

 

On ram usage, yeah, 8gb is rather small (funny when I remember dreaming of 4, and using only two for that past 6 years of my life), I recently upgraded straight to 24 and it's great difference. Ram is rather cheap at this time too ! It's good investition.

[stayinwonderland]

Thanks again. More invaluable tips. I diiid wonder about material displace vs modifier, now that confirms it. I also pondered the merits of baking the thing too (not that i know how to do that but food for thought). I might go and do the extra 8 gigs of ram too. Right, lessons learned then, i shall hopefully have dispensed with 24hr+ render times!

 

Edit: just checked out your website. Man, your work is phenomenal. Takes a good 3d artist to make another 3d artist wonder whether there are photographic elements etc.

Edited January 22, 2012 by stayinwonderland

[RyderSK]

Thank you Andy. By "baking" I didn't mean any special process. It's just the name for applying the modifier for the geometry so it actually changes it in viewport. It's called "displace" and it doesn't produce any aditional subdivisions, just lifts the geometry according to heightmap input. This of course isn't good approach if you use endless sea :- ).

Then you can put Vray Displace modifier on top of it, and use either 2D aproach (very fast ! but doesn't pick light so properly and only works with heightmaps) or 3D (slower, huge ram usage, but can be easily optimised unlike material displacement, which has zero adjustments and result is unpredictabe), 3D picks up light very good since it completely changes the geometry, and can be used with procedural maps.

[stayinwonderland]

Cool, I can confirm that when i up the dynamic memory to 4096, it's drastically quicker. No 'unloading geometry'. And also seems quicker due to using vraydisplace in the modifier stack vs the material. Whole scene is much more manageable now

[AubreyM]

Glad it worked out for you.