question

Eden Exposito avatar image
Eden Exposito asked ·

Share operator look file from C4toA to HtoA, not work properly?

Hello!

I have added an alembic (in arnold procedural object) in C4D and I have applied an arnold shader (chrome metal) with operators, all seems works properly inside C4D. Then I'm trying to share a "look file" (.ass file input graph) from c4d to Houdini, but when I try to apply ass file exported from operator nodegraph and try to apply to my alembic file in Houdini I see nothing.

I attach some screenshot, and .abc file with operator ass file to test it




operators.zip

operator
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Stephen Blair avatar image
Stephen Blair answered ·

This is what I did:

  • In CINEMA 4D, I create an Arnold Procedural object
  • That Arnold Procedural object loads the abc you provided.
  • I create an Arnold shader.
  • I create an Arnold Operator that uses Set Parameter to assign that Arnold Shader to a selection of the objects in the abc file.
  • On the Arnold Procedural > Overrides tab, I set Mode to operator network and select the operator that I created.
  • I render and it works.
  • From the Operator Network, I export the operator to file
  • In Houdini, I create an arnold procedural and the abc file you provided
  • In the out context, I create an include graph and load the operator ass file I exported from CINEMA 4D
  • In the arnold procedural node, I set Operator Graph to the include graph node.
  • I render and it works.
  • I go back to CINEMA 4D, and in my operator, I put in an Include Graph and load the operator ass file. That works too when I render.
Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Eden Exposito avatar image
Eden Exposito answered ·

Thanks for your response @Stephen Blair,

When you say: "Both these work for me (when they are in the ass file exported from CINEMA 4D and used in Houdini)"

We talk about same? I mean add .abc inside Arnold Procedural object in C4D and Houdini correct?


abc.jpg (386.6 KiB)
Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Stephen Blair avatar image
Stephen Blair answered ·

Both these work for me (when they are in the ass file exported from CINEMA 4D and used in Houdini)

"/objects/*Sp*_geo/*"
"/objects/Tube_mesh/*"


1 comment Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

And 1.ass works too, because the selection string is

 selection "/objects/*Sp*"


0 Likes 0 · ·
Eden Exposito avatar image
Eden Exposito answered ·

Thanks for your response !

If you apply a selection expression without restrict it a group in the alembic, works properly in C4D and Houdini. The problem is when you want to restrict this *here_geoShape selection to works only inside /object/ group in this case (think about you have same name objects in two differents groups in alembic file /objects1 and /objects2 but you only whant to select objects inside /objects1 group)

Seems like in C4D you need to specify Arnold Procedural object ("assets" in this example), to found /object group. But in Houdini this step seems not be necessary, with /object/*here_geoShape all works correctly in Houdini. The BIG problem is when you try to solve in C4D adding /assets/objects/*here_geoShape , now C4D found /object/ group, but Houdini not...

Then, How to restrict object selections in an alembic group that work in both softwares correctly?

(to avoid false positives when you try it please, start and stop IPR everytime that you change selection expression to refresh)

Thanks!!


1.jpg (485.1 KiB)
2.jpg (488.9 KiB)
3.jpg (479.0 KiB)
Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Stephen Blair avatar image
Stephen Blair answered ·

The attached worked for me. It puts a Utility shader on the two spheres.

Selection string is *here_geoShape (to match Sphere and Spehere in the abc file)

In Houdini:

- An arnold_procedural node that loads the abc file

- Operator graph is an include_graph


I did not try with an alembic node, and probably won't until tomorrow when it's supposed to rain...today I will be out in the yard or napping ;)


Arnold Operators.ass


Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Eden Exposito avatar image
Eden Exposito answered ·

In previously attached abc file you can see that objects are inside group calle "objects". Here I attach 3 look files exported:


Number 1 - Export with Selection mode "expression" and write for select spheres: /objects/*Sp*

This work ok in Houdini but no in C4D

Number 2 - Export with Selection mode "procedural" select procedural object called "assets" with abc inside and write for select spheres same expresion: /objects/*Sp*
This work ok in C4D but no in Houdini (in exported file you can see that path is really wrote as /assets/objects/*Sp*)


lNumber 3 - Export with Selection mode "expression" and write for select spheres: /*Sp*

This work ok in both C4D and Houdini.


If number 3 works on both Is very strange that number 1 only works in Houdini and not in C4D,


Thanks!

3.ass

1.ass2.ass


1.ass (3.9 KiB)
2.ass (3.9 KiB)
3.ass (3.9 KiB)
Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Eden Exposito avatar image
Eden Exposito answered ·

The problem seems be related with selection mode when you create a collection.In C4D i need select mode "Procedural", select arnold procedural element and the write expression to see changes in IPR. But when I export this look to Houdini I see nothing in Houdini IPR.

Otherwise if In collection I choose selection mode "expression" and write same expression I see nothing in C4D IPR but when I export look file to Houdini I see correclty there.

It's make no sense for me, How I can create collections to work properly in both applications?



lookdevc4d-main.jpg (656.3 KiB)
Share
10 |600 characters needed characters left characters exceeded

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Write an Answer

Hint: Notify or tag a user in this post by typing @username.

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Welcome to the Arnold Answers community.

This is the place for Arnold renderer users everywhere to ask and answer rendering questions, and share knowledge about using Arnold, Arnold plugins, workflows and developing tools with Arnold.

If you are a new user to Arnold Answers, please first check out our FAQ and User Guide for more information.

When posting questions, please be sure to select the appropriate Space for your Arnold plugin and include the plugin version you are using.

Please include images, scene and log files whenever possible as this helps the community answer your questions.

Instructions for generating full verbosity log files are available for MtoA, MaxtoA, C4DtoA, HtoA, KtoA, and Kick.

If you are looking for Arnold Documentation and Support please visit the Arnold Support site.

To try Arnold please visit the Arnold Trial page.

Bottom No panel present for this section.