Vray gpu displacement

[eXeCuze]

Okay guys, can someone please explain to me what the exact differences are between the 3 different displacement types. And also, which one is recommended? I read the documentation and here they recommend either 3D mapping or subdvision but or i don't get the expected result, or my whole scene turns painfully slow. I have been using Vray now for many years and this still is a mistery to me. On other engines you simply have displacement, which works in all use cases and is fast.

I probably am doing something wrong, but it would be great if someone can explain this in more detail to me.

Thanks in advance!

[Muhammed_Hamed]

Hello eXeCuze

I personally always use 3D Displacement in Vray, because it supports procedural noises and doesn't require the object to have UVs. Subdivision works in the same way, but 3D Displacement has easier/better controls.

Usually displacement maps range from 0.0 to 1.0 with 0.5 (half grey) would be no displacement, white is up and black is down. In Vray the amount value(in V-ray displacement modifier) determines how much displacement is the white, and it only goes "out" the geometry so black means no displacement. So in addition of using the "amount" value, you also need to use the "shift" amount by half of the negative amount, so, if you want an amount of 1.0 the shift should be -0.5. This will make the displacement to be shifted down by 0.5 and this way a grey value of 0.5 will represent no displacement.

If you have a scene I will be able to tell what is going on

Best,
Muhammed

[eXeCuze]

Hi Muhammed,

Thank you for your reply. I am mostly using 32bit displacement maps coming out of Zbrush. And i am currently using the subdivision method, because i have the idea that this gives a slight memory advantage, but i am not sure about this.
I always was using this method: https://www.cggallery.com/tutorials/displacement/

But now i read the docs on the chaosgroup website and i am wondering if the added turbosmooth modifier still is needed?

[Muhammed_Hamed]

because i have the idea that this gives a slight memory advantage

It is not a slight memory advantage, displacement on GPU is memory-intensive.. every increment will have impact on memory consumption

i am wondering if the added turbosmooth modifier still is needed?

Pretty sure the answer is no, Edge length takes care of that.. 4 is good, sometimes I use 2