topic Is it possible to Export alembic with textures? in ArcGIS CityEngine Questions

Is it possible to Export alembic with textures?

AbeleGiandoso — Sat, 03 Nov 2018 18:01:21 GMT

Hi all

I see in the tutorial section about exporting models in abc file format, that alembic files imported into Maya seems to be retaining their textures (at least the pictures show textured assets).

How can I do it?

I thought abc files did not have texture information, just the uvs, and all the test I made so far produced geometry without shaders or textures (although the textures themselves were exported in the same folder) just the one initial shader Lambert 1.

The abc format is much lighter and manageable than FBX but without tetextur is not very useful, so if there is a procedure I am missing please let me know! I'd love to learn it

Thanks

Re: Is it possible to Export alembic with textures?

SimonHaegler — Wed, 07 Nov 2018 15:28:20 GMT

Hi,

Yes, Alembic files support texturing.

I assume you are expecting to see textured models in the Maya OpenGL viewport? This is not by default supported by the Alembic plugin in Maya (at least not in our tests with Maya 2016 a while ago). The screenshot in the tutorial with textures actually shows the Vray render window and not the Maya OpenGL viewport.

The idea of the Alembic workflow is to only load the textures at the very end in the renderer (Renderman, Arnold, Vray, etc). In this way, Maya can display large scenes in preview mode interactively with overloading the GPU and system memory. This workflow is mainly designed for large VFX production scenes or high-end architectural visualization.

In theory one could write a script to extract the textures from the Alembic file and attach it to the Maya OpenGL preview materials, but this is quite involved.

I suggest you work with the Arnold IPR rendering mode if you need to work with the textures before final render.

I hope this helps & best,

Simon

Re: Is it possible to Export alembic with textures?

AbeleGiandoso — Wed, 07 Nov 2018 16:26:32 GMT

Hi Simon.
This is great news!

This workflow is mainly designed for large VFX production scenes or high-end architectural visualization.

I have a very very large scene so this is great actually!

In theory one could write a script to extract the textures from the Alembic file and attach it to the Maya OpenGL preview materials, but this is quite involved.

This is not necessary, I only care for the final render. One thing I need to do though is replace all materials that are automatically set as Phong (outdated) with a Arnold standard material which follows energy conservation and allows easy PBR.

I did make a test, and exported a single block in abc format from Esri.

I imported it in Maya (drag and dropped it in the scene) and I tried to render it in Arnold but it shows only a white default Lambert Shader in the Arnold render view. In the Hypershade there are no Materials only the basic Lambert1.

Would you be able to tell me what I am doing wrong? Maybe there is a specific workflow and I am not aware of or something I am doing wrong. Any guidance will be of help.

Many thanks for your assistance.

Re: Is it possible to Export alembic with textures?

SimonHaegler — Wed, 07 Nov 2018 17:22:32 GMT

Hi Abele,

In the docs there is a diagram how we attach the CityEngine/CGA material properties (and arbitrary attributes/reports) to the Alembic tree: Alembic ABC Export

I did not yet work with Arnold and Alembic. Based on my experience with Houdini/Mantra and Maya/VRay, the workflow actually requires that there is a translation step from the Alembic (material) properties to the Arnold materials. For example, in Maya/VRay this is done by the included python script in the tutorial.

I guess this section of the arnold for maya guide should get you started: Modifying an Alembic Procedural Using Operators - Arnold for Maya User Guide 5 - Arnold Renderer

Best,

Simon

Re: Is it possible to Export alembic with textures?

AbeleGiandoso — Wed, 07 Nov 2018 17:39:00 GMT

Hi Simon.

Thanks for the information

I don't know how to script sadly, my technical knowledge starts and ends with CGA. I might have hit a wall here 😕 It is a pity because FBX is just terrible as a format.

Since now Arnold is Maya default render it would be extremely useful for the future iterations to consider a tutorial and a script like the vray one provided in the help files.

It would go together with my suggestion for a general PBR upgrade (new uvsets for rougness and metallic and height maps)

Thanks for all the help

Re: Is it possible to Export alembic with textures?

SimonHaegler — Wed, 07 Nov 2018 17:47:44 GMT

Thanks for the feedback.

We have PBR support on our roadmap and did already a number of investigations - support for it will definitely come in one of the next releases, no promises though when exactly

We also have good contacts with the Arnold guys within Autodesk and will definitely look into supporting it more directly.

Best,

Simon

PS: Maybe Houdini (free learning edition) could be an alternative in the mean time? Alembic import is great and there is a small spare-time project I do with a friend: GitHub - Esri/palladio: Palladio enables the execution of Esri CityEngine CGA rules inside of SideFX Houdini.

Re: Is it possible to Export alembic with textures?

AbeleGiandoso — Wed, 07 Nov 2018 17:51:28 GMT

I was seriously thinking about learning Houdini

This might really be the right motivator. Thanks!