Does anyone know how to add the second or third uv to geometry in Houdini?

Most of the uv tools have a paramter to define the name of the uv attribute used. Change the default ‘uv’ to something else. The uv attribute name can be as simple as ‘uv2’ or a descriptive name such as ‘detail_texture’.

Great!
I'd like to export the mesh with the second or third UV into the game engine.
Hope it works well.

Thank you so much.

Unfortunately, I added a new uv attribute named ‘uv2’, but the second uv in 3dmax was not same as the houdini's after I imported the hda file.
I'd like to make a model with the second/thrid uv through houdini since my shader needs it to add some detail in Unreal Engine, and I want to finish it in houdini, it looks so cool, although I can adjust it in 3dmax.

A couple of things I've gathered from using alembic to go from 3ds Max to Houdini and back:

- Any secondary or higher uv map channel will come in named Max_Map_Channel_2, Max_Map_Channel_3, etc and comes in with a corresponding local variable “Max Map Channel 2”, etc and needs to be exported out the same way. Map Channel 1 will come in as just “uv” attribute.

- If you're creating a Max_Map_Channel_2 in Houdini, you need a local variable connected with that too. You can create the local variable by using an attribute create specifying the local variable as named above and uncheck Write Values since you'll probably have the uv from a texture node or something else.

- Other uv channels will also probably come in as vector class instead of just the 3 float like regular uvs, so that means be careful with any transforms because they will affect your Max_Map_Channels unless you tell them to ignore them, ie: scaling down or up. They will also come in rotated 90 degrees in the x axis cause of Max being Z-up and alembic bringing them in to a Y-up environment. You can change the vector type if you want using a wrangle.

- If you're trying to have vertex color in addition to these additional uvs, 3ds Max will bring in the uv attribute first (map channel 1), then the vertex color, then the additional map channels which screws up the normal way in Max of the vertex color first, then the first map channel (uv attribute), and so on. So before exporting from Houdini, you could rename your uv attribute to Max_Map_Channel_1 and give it the local variable “Max Map Channel 1”, and your vertex color should come into Max first, then the ordered map channels. I don't remember if just having one uv channel and vertex color screwed up the order in Max or not though.

If you want to inspect how Max likes alembics, you can save out a sphere with multiple map channels and bring it into Houdini, then look through how it's coming in.

-Mike

Yes, you can. For example, if you put a UVUnwrap node, you'll see UV Attribute which is set to UV. That is basically the uv channel. Add another UVUnwrap node after the first one and put another name for the UV Attribute of it, UV2 for example. Export it to Unreal for example and you'll see both UV channels.

As stated previously, the UV Attribute parameter is present for most of the UV tools.

I did it!
Thanks for your information.

azeroc
Yes, you can. For example, if you put a UVUnwrap node, you'll see UV Attribute which is set to UV. That is basically the uv channel. Add another UVUnwrap node after the first one and put another name for the UV Attribute of it, UV2 for example. Export it to Unreal for example and you'll see both UV channels.

As stated previously, the UV Attribute parameter is present for most of the UV tools.

Thank YOU!!!!
I made small asset just add it to the shelf.