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Quick question about Iray Canvases

SnowSultanSnowSultan Posts: 3,775
edited September 2015 in The Commons

I know that you can use Canvases (in the Advanced tab of the Render Settings panel) to render alpha masks and other individual passes, but is there a way to render only selected items with all passes (diffuse, spec, bump, etc) while retaining the shadows and AO of other hidden objects? Basically I want to do what "Fantom" in the UberSurface2 shader does.

"Beauty" renders an b/w alpha channel, and all of the other options are for one specific parameter (diffuse only, spec only, etc). I don't see an option to normally render only the selected.

Thanks in advance!

 

EDIT: Huh, I restarted Studio and now Beauty passes are working as I expected (rendering only the selected with all parameters). Not sure why it wasn't working before but this seems to be solved. Maybe it has something to do with the Active Canvas drop-down not auto-updating unless you add a second Canvas?...oh well, this is a very useful feature and I hope more people take the time to play with it.   :)

Post edited by SnowSultan on

Comments

  • Oso3DOso3D Posts: 15,085

    I was experimenting with that stuff during one of my experiments to get drawn style with Iray. Kept running into the annoyance of transparency (most of the channel stuff doesn't recognize transparencies, which greatly complicates hair and other things)

     

  • ToborTobor Posts: 2,300

    A single Beauty pass with nodes selected should do it. It's easy to forget to select the node list after creating it. It's a two-step process.

  • Cris PalominoCris Palomino Posts: 12,484

    Snow, I beleive someone did explain that; I'll look for the thread.

  • SnowSultanSnowSultan Posts: 3,775
    edited September 2015

    Timmins: I don't think we'll ever be able to get a drawn style out of Iray, it's simply not what it's designed for. Stick with 3Delight for that or Photoshop the stuffings out of it.   ;)

     

    Tobor: Yes, I found that's the best method. The Alpha options (both the selection and the checkbox) seem to give unpredictable results.

     

    Cris: Thanks very much but don't go to too much trouble.   :)

     

    Post edited by SnowSultan on
  • Oso3DOso3D Posts: 15,085

    Well, I have a semidrawn style that I enjoy, so ... yay!

     

  • ToborTobor Posts: 2,300
    SnowSultan said:

    Tobor: Yes, I found that's the best method. The Alpha options (both the selection and the checkbox) seem to give unpredictable results.

    The Alpha canvas is a 32-bit EXR image, and needs further toning processing in Photoshop or compositor.

    The checkbox should work, unless your scene has content that the normal alpha channel masking may not handle properly. There is a separate entry in the Render panel for how the Alpha is traced. You can also write your own light path expression, but one of the three "stock" methods should work for most tasks.

     

  • Cris PalominoCris Palomino Posts: 12,484

    Yeah, actually it was something Tobor wrote up that I was thinking was it.  http://www.daz3d.com/forums/discussion/comment/877787/#Comment_877787

    That post was what led me to experiment with canvases.

  • SnowSultanSnowSultan Posts: 3,775
    edited September 2015

    That's good Timm, glad you found a style that works.  :) 

     

    Tobor: Hm, when I was rendering an Alpha canvas as a test, it appeared to be entirely black. If it's opened in Photoshop, will it appear differently? It's not that big a deal because I will use Mask and Multipass Tookkit for material masking anyway, but I couldn't understand why it didn't appear to do anything.

     

    Thanks Cris, that's a good tutorial for anyone wondering what Canvases do. Very helpful to do individual Beauty renders when you have complicated scenes, and they even work with spot rendering if you tell it to render in a new window.

    Post edited by SnowSultan on
  • kitakoredazkitakoredaz Posts: 3,526

    I am now lerning parameters of iray uber shader one by one, then hope to know about material ID color.  it seems to be used with canvases. but I do not know how I use them.  What can I do if I set Material ID as colors  for surface groups?  I checked daz documents , but How I use them?coolhttp://docs.daz3d.com/doku.php/public/software/dazstudio/4/referenceguide/interface/panes/surfaces/shaders/iray_uber_shader/shader_general_concepts/start

    Material ID - Use this to set a color to flag or group particular materials. Material ID is used by Iray in Render Settings > Advanced > (check) Canvases > (click +) Type > Material ID Canvas.

    Then I set color (255 0 0)  for "surface group 1"  Material ID,  and set (0 255 0) for "surface gorup2" material ID.after that,  I add new Canvas1.MaterialID , in Render setting.

    but I have no idea how it work. I hope to know example of use "Material ID with canvases".  what Can I try for test?

    matid.PNG
    1173 x 677 - 542K
  • ToborTobor Posts: 2,300

    SnowSultan, You need to open all the EXRs in a 32-bit compliant application, and then tone map for the appearance you want. When viewed with an 8-bit program, you only see the "bottom eight bits" of the image -- that is the lower part of the 32-bit range. That's why it often appears as black.

    Kitakoredaz, you use MaterialID mostly for compositing. Each material, or group of similar materials, can be assigned a distinct color. You then use the color picker/selection tool in your graphics program to create masks of these areas. Once masked you can then hide/show different parts of your image. For example, you can create a mask of the hair so that in your graphics program you can apply some special effect or filter to just the hair.

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