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Iray Ground Shadows without HDRI?

Leonides02Leonides02 Posts: 1,379
in The Commons

Hello All,

I've been messing with Iray, trying to create a transparent render with ground shadows. I can do it with an HDRI easily enough, but I'd like to use my own in-scene lights. The Iray ground doesn't seem to like them at all.

I've tried to set up the Iray matte material shadow catcher, but I think something has changed since the older tutorials. They aren't making shadows anymore.

Any suggestions? Thank you!

Comments

  • L'AdairL'Adair Posts: 9,479
    Leonides02 said:

    Hello All,

    I've been messing with Iray, trying to create a transparent render with ground shadows. I can do it with an HDRI easily enough, but I'd like to use my own in-scene lights. The Iray ground doesn't seem to like them at all.

    I've tried to set up the Iray matte material shadow catcher, but I think something has changed since the older tutorials. They aren't making shadows anymore.

    Any suggestions? Thank you!

    1. Check the Render Settings->Environment for the Draw Ground setting and make sure it is On.
    2. By default, the Ground Position Mode is set to Auto. If you have something in the scene that is lower than your primary object, it could be forcing the auto ground position too low. If so, change Auto to Manual.
    3. Even if Ground Position Mode is set to Manual, if the objects are above the ground plane, their shadows may not show. (And the may not be what you were trying for, if they were visible.) for example, some poses created for specific sets may be "go to" and move the figure to another location. Moving the camera to frame the figure in the shot could easily put the ground out of frame. In Perspective view, click on the icon of a filled circle with an up arrow. That will bring you back to the default view, with world center in the frame. If the subject of your scene isn't there, that may be part of your problem.

    Let us know if any of these solve the problem, or if you still need help.

  • Leonides02Leonides02 Posts: 1,379

    Hello L'Adair,

    Thanks for your reply! 

    I get the ground shadows fine when using an HDRI and setting the dome to "off" and ground to "on."

    However, if I change to render to "use scene only" or if I remove the HDRI (or change the time to, say, midnight) then the shadows disappear.

    It appears like the ground only catches shadows made by the dome....

  • xmasrosexmasrose Posts: 1,409
    edited January 2019

    If I understood you right, I don't have the same problem. Using DS 4.10.

    One distant light only

     

    DS scene only.jpg
    558 x 530 - 256K
    DS scene only2.jpg
    398 x 343 - 81K
    Post edited by xmasrose on
  • L'AdairL'Adair Posts: 9,479
    Leonides02 said:

    Hello L'Adair,

    Thanks for your reply! 

    I get the ground shadows fine when using an HDRI and setting the dome to "off" and ground to "on."

    However, if I change to render to "use scene only" or if I remove the HDRI (or change the time to, say, midnight) then the shadows disappear.

    It appears like the ground only catches shadows made by the dome....

    To get shadows, you need a light in the scene that is "visible." HDRI, Sun, Spotlight, Distant Light, even a mesh light with opacity.

    In the Sun-Sky Only mode, you need to set the date, longtitude, and latitude as well as the time of day. If you set the time to Midnight, the coordinates for the locale will need to be pointing to somewhere near the north or south poles with a date that corresponds to that pole's long days. Otherwise it is night, the sun is on the other side of the globe, and there is no light.

    In Dome Only or Dome and Scene, the HDRI will light the scene whether or not you use Draw Dome. In Dome Only mode, if you remove the HDRI, there is no longer any light in the scene. The same is true in Dome and Scene mode, unless you added other lights. In fact, without any light, all you should get are silhouettes of the objects in the scene, (with Draw Dome off.)

    Based on your posts, I'm thinking you have some light in the scene, which begs the question:

    What lights do you have in your scene?

  • Leonides02Leonides02 Posts: 1,379

    Thanks again for your help. I'm really confused by this!

    Distant Lights definitely create a (very harsh) shadow:

    But mesh lights don't:

    Nor do spotlights:

    image

    I don't know.... sad

  • xmasrosexmasrose Posts: 1,409

    You're right!!!!!

    But I tried a mesh light from https://www.daz3d.com/render-studio-iray it works but if I create a mesh light from a plane primitive it doesn't work.

    No clue why.

  • JazzyBearJazzyBear Posts: 805

    Try dome and scene. 

    Also the time and date do not work if there is a file in that section for environment.

    You can also put down a primative plane halfway under an object and make sure the ground and the plane are receiving shadows the same way. If not it will point you to what you need to change.

  • Leonides02Leonides02 Posts: 1,379
    xmasrose (aka tulipe) said:

    You're right!!!!!

    But I tried a mesh light from https://www.daz3d.com/render-studio-iray it works but if I create a mesh light from a plane primitive it doesn't work.

    No clue why.

    So strange! The mesh light I used was also not a primitive. I may pick up Render Studio Iray just to see what the difference may be...

  • xmasrosexmasrose Posts: 1,409

    It is a great product. You won't regret getting it.

    Have you tried to apply an Iray Matte node?

    I succeded in applying it to a plane (which then became invisible) and rendering, in scene only mode, with a spot light. It seems it can be applied to a light but I didn't find any details about it and has no success. If anybody knows please help.

    https://www.daz3d.com/forums/discussion/comment/897469/#Comment_897469

    https://www.daz3d.com/forums/discussion/57051/how-do-you-create-a-shadow-catcher-in-iray

  • xmasrosexmasrose Posts: 1,409

    As a matter of fact it works on a mesh light.

    I used a primitive plane and with the script "create advanced iray node property" I created the "enable iray matte" (turned it on) on the mesh light and the shadow is visible.

  • Leonides02Leonides02 Posts: 1,379
    xmasrose (aka tulipe) said:

    As a matter of fact it works on a mesh light.

    I used a primitive plane and with the script "create advanced iray node property" I created the "enable iray matte" (turned it on) on the mesh light and the shadow is visible.

    Wait, using the "enable iray matter" caused a shadow to appear on the ground?

    Or do you mean it caused a shadow to appear on the primitive you place under the figure?

  • xmasrosexmasrose Posts: 1,409
    edited January 2019

    On the ground, no primitive under it with the mesh light. But it makes the mesh light slighlty visible (it is not if I turn iray matte off) as you can see. Rendered in Scene only mode with "Ground shadow intensity" push to 3. (The file is a PNG with transparency.)

    With the spotlight I could only make a shadow appear on a primitive plane (with an iray matte node) but the plane becomes then invisible.

    19_mesh light shadow ground.png
    600 x 480 - 86K
    DS scene.jpg
    962 x 689 - 172K
    Post edited by xmasrose on
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