Curves and Cd in Octane 2018 not working

Forums: Curves and Cd in Octane 2018 not working
Houdini Integrated Plugin

Moderator: juanjgon

Curves and Cd in Octane 2018 not working

Postby fantome » Wed Jul 10, 2019 9:45 am

fantome Wed Jul 10, 2019 9:45 am
Hi guys

I use octane 2018, with the new Color Vertex Attribute node.

On a polygonal faceted object everything work as expected , i can access Cd as a point / vertex attribute
But when using a polygonal curves , i just can't make it work, i use the render as curves feature in Objparms fur tab.
=> so does the new feature work on curves object or not ? if not is this a houdini plugin restriction or an octane core restriction ?

When i use the old trick of storing Cd as a prim attributes, then activating Pack color in the UV map , and remap throw rgb4k_map.ppm it does works.
=> so does the old workflow is still the default workflow to render Cd attributes on curves with octane 2018 ?

I would need to export this workflow to octane standalone , problem is when i try to store manually @Cd as @uv at prim level it does render some color but not the good one.
So i guess that the feature of storing @Cd in the uv map is not as simple as copying Cd to UV. There must be some black box voodoo that i can't reproduce.
=> juanjo would it be possible to explain exactly how you store and remap @Cd in @uv and how to interpret it correctly throw rgb4k_map.ppm ?

Thanks a lot for your lights
Cheers
E
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm

Re: Curves and Cd in Octane 2018 not working

Postby juanjgon » Wed Jul 10, 2019 12:14 pm

juanjgon Wed Jul 10, 2019 12:14 pm
Hi,

Yes, sorry, the user attributes are not working in the curve objects yet. This feature is only available for the mesh objects currently.

I don't understand your second question. If you export a scene from Houdini to .orbx including the Cd attribute packed in the UV maps, it should be rendered by the Standalone without problems. As you say there is some math to encode the attribute into the UV map to reference the exact color from the .ppm file.

Thanks,
-Juanjo
Computer Graphics Software Developer
Octane plugin development and support: LightWave and Houdini
User avatar
juanjgon
Octane Plugin Developer
Octane Plugin Developer
 
Posts: 6845
Joined: Tue Jan 19, 2010 12:01 pm
Location: Spain

Re: Curves and Cd in Octane 2018 not working

Postby fantome » Wed Jul 10, 2019 12:39 pm

fantome Wed Jul 10, 2019 12:39 pm
Thanks for your fast answer Juanjo.

For the user attributes not working on curves is this an octane render limitation ? or does the feature exist in standalone but you need some time to implement the feature at plugin level ? I ask this because i haven't suceed to make it work in standalone either.

Well i might be wrong but .orbx export enter in the scope of a full feature houdini license. I am using Houdini Indie, and i'm afraid in my case the .orbx export is not an option because it's a locked feature for Indie users ?

Would it be possible to share the math code that allow you to convert @Cd and @Alpha to a uv channel. It would be great to be able to have access to this manually and put your code inside a primitive vex wrangle to generate @uv and @uv2 attribute and be able to export them directly in the .abc then be able to plug the rgb4k_map.ppm in standalone direcly. That would allow to bypass .orbx export restriction. And thus be able to render hair/curves color directly in standalone. An other option would be ta add a checkbox in the Objparms just below the export att checkbox to be able to write the attribute in houdini.

Capture.PNG


Cheers
E
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm

Re: Curves and Cd in Octane 2018 not working

Postby juanjgon » Wed Jul 10, 2019 6:11 pm

juanjgon Wed Jul 10, 2019 6:11 pm
Sorry, this is an Octane render limitation. The custom attributes are only available for the mesh objects, but I suppose that this feature will be expanded to other geo types and the instances in the future.

I'll send you a PM with the maths behind the Cd to UVs attributes encoding.

Thanks,
-Juanjo
Computer Graphics Software Developer
Octane plugin development and support: LightWave and Houdini
User avatar
juanjgon
Octane Plugin Developer
Octane Plugin Developer
 
Posts: 6845
Joined: Tue Jan 19, 2010 12:01 pm
Location: Spain

Re: Curves and Cd in Octane 2018 not working

Postby fantome » Wed Jul 10, 2019 8:11 pm

fantome Wed Jul 10, 2019 8:11 pm
Thanks a lot for your fast answer Juanjo.

It works perfectly , i can now export Cd att on curves to standalone and c4d this is really great cause cv's eat far less vram.
Does the code you give me handle both @Cd and @Alpha, or do you have an other code to map correctly throw alpha4k_map.ppm.
If the code is different would it be possible to also share it ?

Thanks again for your great support
Cheers
E
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm

Re: Curves and Cd in Octane 2018 not working

Postby juanjgon » Thu Jul 11, 2019 9:19 am

juanjgon Thu Jul 11, 2019 9:19 am
It is the same code, but you must use the "alpha4k_map.ppm" map, usually linked to the opacity channel, to manage the alpha values.

Thanks,
-Juanjo
Computer Graphics Software Developer
Octane plugin development and support: LightWave and Houdini
User avatar
juanjgon
Octane Plugin Developer
Octane Plugin Developer
 
Posts: 6845
Joined: Tue Jan 19, 2010 12:01 pm
Location: Spain

Re: Curves and Cd in Octane 2018 not working

Postby fantome » Fri Jul 12, 2019 6:39 am

fantome Fri Jul 12, 2019 6:39 am
thanks for your fast answer Juanjo.

I can' t make it work for the moment.
- if i set rgb value to their @Cd equivalent and set alpha to 1. the color works perfectly with rgb4k_map.ppm.
- if i set rgb value to 0 and set alpha to @Alpha. the alpha works perfectly with alpha4k_map.ppm.
- BUT when i set rgb with @Cd AND alpha with @Alpha, the colors works but the alpha fail.

i would have several question in order to fix the problem.
- internally do you only use @uv.x and @uv.y at prim level to set the 4 value R, G, B, A ? in other words does your tricks allow you to store 4 float values(r,g,b,a) in a 2 float value (uv.x, uv.y) ?
- or do you use one value @uv to store RGB and an other one @uv2 to store the Alpha
- i interpret the ppm map to be in linear space in the texture loader , is that correct ?
- i have try to store 2 different uv attribute : @uv and @uv2, one for @Cd the other for @Alpha. But it looks that the Projection UVW node, doesn' t work at prim level ? it only work with UV set 1, whatever i do i am unable to access UV set 2 at prim level ? can you confirm it' s normal and that the feature is not supported , or is this a bug ?

Thanks again for your support and sorry for the big list of questions
Cheers
E

EDIT:
Ok juanjo i got it !
- primitive uv are not supported by octane
- in order to render curves Cd/Alpha you have implemented only one @uv channel that is able to store r,g,b,a inside only 2 channel @uv.x and @uv.y (which is really clever by the way)
- multiple uv set won't work at prim level
- ppm map must be interpreted as linear space map
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm

Re: Curves and Cd in Octane 2018 not working

Postby fantome » Wed Jul 17, 2019 9:33 am

fantome Wed Jul 17, 2019 9:33 am
Hi JuanJo !

i would have an other question related to this subject, but before that i would like to make a brief sum up of what is working to export different type of geometry from houdini to octane standalone(OS).

Faceted Polygon Object : Cd / Alpha and any other attributes can be exported as a Point OR Vertex attribute and then read in OS with color vertex attribute and greyscale vertex attribute node.
this method doesn' t work yet with curves object and particles object.

Curves Object : Cd / Alpha and width are the only attributes that can be exported throw the @uv primitive attribute and @width point attribute. @width is directly recognised in OS, but to be able to use @Cd and @Alpha, we need to use your code tricks to pack @Cd and @Alpha into @uv.x and @uv.z. Then to unpack those info we need to use rgb4k_map.ppm and alpha4k_map.ppm.

Particles Object : @width exported as a point attribute is directly recognised by OS to control radiusPP (@pscale in houdini). In Houdini @Cd and @Alpha can be stored inside the @uv point attribute. Again we need your code tricks to pack @Cd and @Alpha into @uv.x and @uv.z. Then to unpack those info we need to use rgb4k_map.ppm and alpha4k_map.ppm.

My problem now is that when i try to export particles with @uv at point level that contain my @Cd and @Alpha, while it works perfectly inside houdini , and while it works perfectly for curves. it looks that OS is unable to understand uv channel on particles ?

- can you confirm me that in OS attribute uv is NOT supported for particles , but only for curves and poly objects ?
- uv channel support on particles is a feature that you have created by yourself inside the houdini plugin, that is not inherited from octane core dev ?
- Do you have an idea or method to be able to export the info contain in my @uv attribute inside OS for particles ?
- In this regards does octane support some .alembic predifined variable like color or similar things ?

it' s a shame that otoy core dev has implemented user data, but have just done half of the work. generally user data are more useful on curves and particles object type than on poly objects.
so at the end we still need to rely on your clever tricks for most exporting task. i hope you will be able to push the core dev team to update this soon. cause i'm waiting for this feature since 2016 when otoy announced that octane 3.1 that will be ship in fall 2016 will support this.

Thanks again for your great support !
Cheers
E

ps : sorry for the whining session, but it's frustrating :)
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm

Re: Curves and Cd in Octane 2018 not working

Postby juanjgon » Thu Jul 18, 2019 5:33 pm

juanjgon Thu Jul 18, 2019 5:33 pm
Hi,

I've seen that you have posted this question in the General Discussion forum. It is a good idea because, to be honest, I don't know why the particles are not rendered in the Standalone like inside Houdini. In theory, the .orbx file should be able to fully encapsulate the scene, including all the uv attributes and so on, so I wonder if this is some kind of limitation on the .orbx file format side.

Thanks,
-Juanjo
Computer Graphics Software Developer
Octane plugin development and support: LightWave and Houdini
User avatar
juanjgon
Octane Plugin Developer
Octane Plugin Developer
 
Posts: 6845
Joined: Tue Jan 19, 2010 12:01 pm
Location: Spain

Re: Curves and Cd in Octane 2018 not working

Postby fantome » Thu Jul 18, 2019 5:42 pm

fantome Thu Jul 18, 2019 5:42 pm
Many thanks for your answer Juanjo,

i am able to render Cd and Alpha in standalone on curves with the help of @uv at primitive level.
so i think it's because octane core dev haven't exposed the @uv parameter for point when importing abc.
i am sure you can have uv on point in standalone because when you use various projection method like box it has an effect on the points.

i hope they will help me on this. and i really hope they will at last support user data on curves and points.
i have read a lot of user post of people trying to import particles and curves in C4D. i think for people working in fx and motion design those feature are juste very important.
but for octane core dev i'm not sur they really understand our needs as CG artist.
I really love octane , but like many of my friends who have abandonned the ship my patience has limits.

i hope they will finally make things evolve quickly or we might see each other again on an other forum of an other gpu rendering engine i would not mention here :) , where all those feature are supported since a long time !

Cheers
E
User avatar
fantome
Licensed Customer
Licensed Customer
 
Posts: 109
Joined: Wed Dec 16, 2015 3:38 pm
Next

Return to Houdini


Who is online

Users browsing this forum: No registered users and 1 guest

Mon Aug 19, 2019 8:19 pm [ UTC ]