vray proxy - Alembic particle width multiplier

[hsz]

Hi

I have a particle alembic file with some attributes which Im trying to use for the size of particles. I can not figure out how to connect it. I can read color, with no issues and it works but for size, I tried point_size, width, etc, and no luck so far. Am I missing something obvious here?
Attached is the file.

Thanks

[hermit.crab]

I do not understand the issue. What exactly are you trying to do? Setting the user attribute name as 'width' in a VRayUserColor node seems to yield a value of "0,025". Is this not correct? If you wish to override it - there's an alembic particle width multiplier in the VRayProxy parameters.

[hsz]

The value that is reading is incorrect. The point size should be 0.025 and isn't working on my file. When I tried to render I get this, which is wrong.

[hsz]

I do not understand the issue. What exactly are you trying to do? Setting the user attribute name as 'width' in a VRayUserColor node seems to yield a value of "0,025". Is this not correct? If you wish to override it - there's an alembic particle width multiplier in the VRayProxy parameters.

Are you doing anything to the file provided? Or connecting the VRayUserColor to something?

[hermit.crab]

Yes, I simply connected a VRayUserColor with the 'width' attribute to the color so I can check the value and it is indeed 0,025. Do you expect this value (from the color set) to be used as the width multiplier by default? Was it exported with that value?

[hsz]

So did it render correctly on your side, not like the picture that I showed? And yes the width is supposed to be 0.025. But the particle is not reading it.

[hsz]

I really need to figure out why the width attribute is not being read by Vray correctly. if someone else from the team can respond I would highly appreciate it. thanks

[Joelaff]

This may shed some light in things, even if you are not coming from Houdini.

https://docs.chaos.com/m/mobile.action#page/60099789

[hsz]

Hey Joelaff

Thank you for sending that! I knew how to save attributes, but it helped me to try something different. So even though that doc says to rename pscale to width that did not work and Vray does not recognize the width attribute from what I can see even if I save it as a float, as soon as I rename the attribute from width to pscale and that worked and the proxy read the value correctly. That is totally the opposite of what that document says.

1. The equivalent of the pscale attribute is width. You can remap it in a Wrangle node with f@width = f@pscale;

Can this be fixed is super confusing and it totally should be width instead of pscale since pscale is just coming from Houdini.

Here are 2 other .abc one with the attribute width as a float which is (particles2e.abc) does not render correctly even though is the same data.
And the one rename as pscale (particles2d.abc) which renders correctly

[tsvetomira.girginova]

Dear hsz, hello.

Could I take a look at the .hip as well? It will be highly appreciated.

It was always an interesting topic. This article is showing great basic advices:
https://docs.chaos.com/display/VMAYA...embic+Workflow

This forum thread should be considered too.
Please define the used V-Ray versions too (both for Houdini & Maya) to perform the exact same test.

Waiting for your answer.
Thanks in advance.

Best regards,
TS

[hsz]

Hi Tsvetomira, is not Houdini is Bifrost the graph. The only thing that I did is change how is saving the attribute from width to pscale on those 2 alembic files. As I mentioned if I put the attribute as `width` it does not work and if I rename to pscale it works correctly.

[hsz]

Here is the graph. Just in case. Set geo property is setting the attribute.

[tsvetomira.girginova]

Ah, hsz - you meant that pscale is known mostly from Houdini, where it is used.
We have met similar questions about Houdini - Maya translation, that's why I suggested this.

Colleagues will join with ideas and request if anything else is needed.
Thanks for clarifying.