Bercon UV - Random by Object ID

[chadstevens]

I was wondering if someone could shed some light on how this works, I've got a model in SOP's that is split into several chunks, how would I add variation to the Bercon noise / wood uv mapping such as offset and rotation to these chunks?

Cheers.

[david.anastacio]

Hi Chad,

Check out this older posts, you can use the same techniques to offset any input of your noise, offset, rotation, etc.

https://forums.chaos.com/forum/v-ray...te#post1089553

https://forums.chaos.com/forum/v-ray...ll#post1071698

Beat,
David.

[chadstevens]

hi david.anastacio thanks for the quick reply, can you please give me a little bit more info, I've had a look at the links you sent, but I'm not sure how it applies to bercon noise, I'm trying to offset it with object mapping, but there is no input on the UV_GenBercon to add a variance value?
See attached.

Cheers

[david.anastacio]

hi david.anastacio thanks for the quick reply, can you please give me a little bit more info, I've had a look at the links you sent, but I'm not sure how it applies to bercon noise, I'm trying to offset it with object mapping, but there is no input on the UV_GenBercon to add a variance value?
See attached.

Cheers

Sorry, my bad, I didn't meat for it to be used in the uv_bercon, that has no inputs for custom data, or any option to use a custom attribute to drive its options.
since you are using what it seems to be a single object, getting those uv_bercon randomization options to work might be hard.
Give a try at regular mapping (uv channel name), and add offsets to rotation, u and v offsets and even use noises in the inputs, you can build a ton of variations and have full control over it.

[chadstevens]

That, unfortunately, will not work, the whole reason I'm using bercon wood is that it maps in 3d and I don't need to unwrap the models, so the texture looks correct no matter the shape or cut of geometry.
This is the same system I use in 3ds max (where I usually do my work) and there is clearly an option to randomize by object/material, but I'm not sure how to use this function?

Maybe one of the devs can shed some light on this? bdancer

Cheers.

[david.anastacio]

Hi again,

You should give a try to the tri-planar mapping node, the tri-planar has a custom attribute option which is pretty usefull.

Best,
David.

[chadstevens]

Thanks, I often use triplanar mapping, but it is not useful for something like bercon wood where the texture needs to bend correctly around corners etc...

[chadstevens]

I've also got another problem where the procedural texture is swimming when I rotate the geo in SOPs is there a way to transform the geometry in SOPs as world space so it sticks to the correct faces etc...
I read online that using a rest and using the vray object properties -> object reference -> rest attribute should get around this and it does for uv's but not for a procedural texture like bercon wood or noise.

[david.anastacio]

Withou a custom attribute it's impossible to drive those randomizations in a mesh that has only one object (we had a silimar talk about the tri-planar with the devs some months ago).
An object is a geo object or a primitive, if your 4 boxes are part of the same packed primitive they will always be seen as a single object by the render. Custom attributes are great to get around this, so we can get a different value accross those meshes and drive randomizations with it.
The uv_bercon does not support custom attributes so the only way to use it to get the variation you are looking fore is to make sure that each box is a seperate object/primitive, it's woth requesting for it to have a custom attribute to drive the randomization to the devs. And the the same for the uv_bercon coordinates not respecting the reference rest attribute might also have to be requested.

Best,
David.

[chadstevens]

Thanks for all the help david.anastacio I really appreciate it. These seem like important features as it basically makes the usage of bercon maps unusable, and I've tried getting the normal vray noise map to also conform to the rest attribute, but it has the same problem, so if anyone has geometry moving is SOP's it's going to have all kind of issues.

The thing I don't understand is that the Bercon map says it can randomize by material ID, object ID, and particle ID, so I thought maybe I'd have to create a custom attribute like ObjectID or something to get it to recognize those features, but I've not managed to get it to work, so what are they used for then?

Just to clarify when you say "make sure that each box is a separate object/primitive" I do have them as separate primitives, my geometry is not packed and I also have different groups for each section as well as a custom attribute for each chunk but like you say I cannot use custom attributes in Bercon.

So the only way around this issue at the moment as I see it is to separate each chunk into its own Obj level geo which is very tedious and really defeats the point of working in Houdini for this kind of thing.

If any of the Devs could have a look at this and if there is a workaround please let me know. alternatively could I please put in a request to include the features above into Bercon maps and any other procedural maps, because currently, they seem to be unusable in production.

Cheers.