displacement options

[4754simon]

I apologise...I only have the final image attached. I deleted the progress renders when i was archiving my folders.

I just had a quick question regarding 'displacement modifiers'? I used a displacement on this rug (see attached image). The problem is not the result (it looks ok) but the render time is a serious issue.

To render this image with displacement (OFF), the image (approx 3450pixels wide) took 2.5 hours to render. However as soon as i render the image with displacement (ON), it took 17 hours to render.... kill me

My question is...
1. are there alternatives for rendering shag rugs? I haven't used fur before... but i imagine the result would be more realistic and more believable??? Would the speed to render be comparable?
2. are there settings that will drastically affect render times using displacement?
3. For animations..... I assume displacement is out of the question

Any advice, suggestions or links would be appreciated.

[Fekta.studio]

What version of Vray ? And is it 32 or 64 bit? You can try increase the dynamic memory limit to match or exceed your amount of RAM, like 5000 MB or more, for example we got 12GB on machines and I set 100000 MB and I never had such issues with render times.

Also you can try adjust Edge length more than 4 , some like 8 , in some cases I set it even up to 16.

[4754simon]

I am using vray 1.5.SP3a on a 64bit machine.

Thanks for the advice Andro, I'll try increasing my ram.

[Morbid Angel]

displacement inside the interrior is always a problem. There is a couple of things you can do.
One precalculate the irradience map/lc with the displacement off, that will speed up the gi part.
Play around with displacement settings perhaps reduce the quality of it, though based on the image the quality is low as is.
Finally I would apply the displacement in viewport and export that o vray mesh and see if that would make a difference.

[3DMK]

You scene has DOF & one thing I have noticed is that DOF slows down rendering of displaced objects [& those with fine overlapping geometry.] a lot
I have noticed this issue on some recent projects. There is obviously a lot of work for the DOF part as there is so many overlapping polys to calculate.

Also I would use VRay Fur as it seems to use far less memory & give much more control & far more realistic results.

I have also used a free plugin called 'Grass-o-matic' which can give god results although it is a bit of a memory hog.

I would also advise against calculating GI with the rug off as it makes the results flat & lifeless.

Hope this helps

[4754simon]

Thanks for the responses. I will check them out. BTW, the DOF is a post effect--created from z-depth pass.