Two different displacement maps on one object

I have an object and would need to map two different maps as displacements.
Of course I would like to use the Vray Displacement Mod, but it only allows one explicit map channel and as far as I experienced we can only use one vraydisplacement modifier for one object.
How can I solve this problem?

Thanks for any help as always, guys!

Make a composite map of your two different maps and use that as a displacement?

Which explicit channel would the modifier use then?

It only allows one set of mapping co-ordinates to be used, so as long as you can use those coordinates for all of the different maps then you’re fine to use as many bitmaps as you like in a composite map.

Thats my problem - that I cant do that unless I unwrap the whole object. And I guess thats the solution then…
Thanks for the info!

Unfortunately yeah - it’s been requested to try and support multiple coordinates but it’s not in there yet. If you hate doing unwrapping, take a look at xrayunwrap - it’s about 12 euros and it’s seriously good.

I will check it out. Thanks a lot for the tip!

As a very dirty workaround, make your object highpoly. Stick the 1st displacement in a max displacement modifier and the 2nd one in a vraydisplacement

ah, you mean real discplacement along with displacement at render times?
yeah, I was doing that until my scene got to heavy because eventually the client wanted hundreds of the same object in the scene and I didnt have time to replan modelling and stuff..

If you use the 3D displacement mode, you can actually use as many mapping channels as you want. The restriction for one channel is only for the 2D displacement method.

Best regards,
Vlado

Thanks for the pointer Vlado!

Yes I just used 2 different vraydisplacementmods on an object using 3d mode with each having a unique map channel. worked very well! i had one large scale general, soft displacement to create sand dunes and then a smaller scale one for finer detail. very successful.

GREAT!
So it was an urban myth or rather my experience from back then when using 2D mode.

Thanks so much for the info!

actually just tryingh it out with the 3D mapping and it doesnt work for me. The moment I slap a vraydisplacemod on top of another one, the lower ones gets ignored.

how do you do that? what could I possibly be doing wrong?

Do you know what… you are correct. Only ONE displacementmod works on each object. The top one is the only one that gets used. And furthermore, only texture channel 1 is used - anything else is ignored.

Looking back at my sand model I *did* use 2 displacementmods, but the second one was for a very fine dune texture that was actually reading through a bump map, making me falsely think it was the displacementmod being used… it looked exactly as I intended so I didn’t dig any deeper - had no reason to suspect something wasn’t working…!

so actually you’re correct:

1) texture channels are broken in vraydisplacementmod
2) you can’t use more than 1 vraydisplacementmod on a single object

Edit: - for Vray support - to recreate this just stick a VDM on a plane with any texturemap with channel set to 2 or above - you’ll see it won’t work. Similarly, get 2 working VDM+texture maps and you’ll see only the one at top most of the stack will be used. The other/rest will be ignored.

you don’t have to use more than one modifier, just one vray disp with say a composite map as textmap with all the different textures you need (each one with a different map channel) blended together. this works perfectly with 3d displacement.

I think this is the solution.

But it would be nice if the VDM did work if stacked.

it certainly would be nice to be able to control quality and amount of different maps with different modifiers, don’t know if that’s even possible though.

Actually, funny enough, I just got two different maps with two different map IDs to work with the displacement mod.
I just ignored the texture channel in the vray displace mod, left it at 1 and combined my two different maps with a composite map its “addition layer mode”. the maps itself had their properly assigned channels, which were linked to the UVW mapping. it rendered alright at both places!

Edit: oops, didnt realize your two answer concerning my method. haha. But I agree, it would be nice to be able to use two different mods on top of each other. more control!