3ds arnold displace volume in z axis only using arnold noise (or uv image) how?

[BrianDeMetz]

Trying to add some detail to a smoke explosion but only want to map some noise in the z-direction to break up some of the jellyfish. can't determine how to wire this up to displacement so it only maps like a uv and in z direction only. thoughts?

[lee_griggs]

camera_projection?

[madsd · Accepted solution]

Attached a ready to go scene for max 2021.

Note there is a custom node, its a volume displacement node, plug and play type.
Set the UV Transforms x and y tile value to 0 and manipulate the z component.

You are now only sourcing and sending displacement data to the Z channel in world space.

[BrianDeMetz]

thanks very much for that breakdown! would it be possible to save-as to 3ds 2019? in the meantime, will try to rebuild using your description and screen caps. thx again.

[BrianDeMetz]

hey Lee. thx for the idea. i actually did try to wire that up, but the displacement always seemed to be doing the 45deg lean even with the camera straight up overhead. perhaps was wiring it wrong.

[madsd]

2019 version attached.

The reason why you see the 45deg shift in the other thread, is because the noise is living in 0-1 space, so all 3 vectors are pulled out towards the offset, thus 45deg as all 3 pulls.
This is why I send over a scene since you need to fix up these things as well for volume displacement to work correctly, which is why I build a custom OSL node you you dont have to think about it, also note that stepping is disabled in the noise.

[BrianDeMetz]

thanks again - appreciate that extra info.

re: the files, the 1st and 2nd zip both seem to be max 2020. can't open 😕

[madsd]

volumeZ_displace.zip

[BrianDeMetz]

thanks! working with the file now. this helps a ton with this all put together.

[madsd]

That was the plan.

Note you can put the x and y values back to 1.0 and use this to created clouds very easily since displacement always occur on the "face" of the object no matter it's form, so you can sculpt forms and turn them into nice little clouds very easily.

Note the Custom node called "Volume Displacement" save this map out into the plugins/OSL foder in max and it will come up as a normal map when you open max next time.

And you use the value inside the Volume displacement map to push out details from the surface of the underlying geometric shape.

[BrianDeMetz]

Hi,

This is great - just about what I'm trying to do. One thing however is that when I increase the noise strength above 1.0 I'm getting an offset downward instead of centered on the original un-displaced volume. I tried inserting a range node to remap -/+ however it messed it up and it started deforming in x/y instead of z. Thoughts on how I'd increase decrease the strength while keeping the displ centered?

Note that I changed the rig where shown to get more like a noisy wave pattern in Z which is what I'm going for - see attached A/B. Thanks!

arnoldVol_ZnoiseDispl_v001.zip

[BrianDeMetz]

That's fantastic! Thanks again. Was wondering how I'd get the shaders out. Sorry, new to Arnold for production work. Forgive my newbie questions.

[madsd]

Right, amplitude is the only thing you can't touch, it moves it out of its location.
Use size, curl, octaves, gain and phase.
In the UV transform, you can decide to make it tile 5.0 times or 0.1 time, the 1.0 is just some number. So you can stretch the field out like this.
You can also scale the whole displacement up and down inside "Volume Displacement" and crank the only setting in there up and down, it is a multiplier and multiplies everything after the noise and thus only affects the displacement going either in or out.

[BrianDeMetz]

Great! Thanks for that detailed info on the use of the rig. Will adjust some of those params. Thx again.