Some Way to Render Ghostly Characters, Animals, Objects

I tried making a ghost by turning a character transparent and messing with shader settings. The result is visually revolting, especially if animated, because of all the external anatomy you can see through the character--his face through the back of his head, for instance.

Thinking about it, I'm not sure ghosts can be done simply with Iray shader and material settings, because Iray's "rays" go through the 3D mesh of a translucent character, even those parts on the far side that would be hidden if the character were solid.

Think of it like the moon--there's a light side we can see from Earth and a dark side we cannot. Those are the terms I'll use: "light side" for those portions of a solid character's mesh visible to the camera, and "dark side" for those portions blocked from the camera's view.

We could achieve ghostly effects by calculating the dark side faces and HIDING THEM from the Iray renderer. Iray would see the character as a deformed 2D mesh, not 3D, so the shapes of the dark side would not appear in the render. (Think of Roadrunner hitting Wile E. Coyote with metal plate, instantly deforming the plate into the shape of Wile E.'s surprised face.) To the light side, you could apply whatever effects and translucency you want in order to get ghostly looks or the appearance of an energy being, and in the render you'd see all normal background objects through the body of a translucent character. But you wouldn't see any dark-side anatomy--no eyeballs floating in the skull, no ear on the other side of the head, etc.

Is it possible to create a shader that performs hidden-face removal before texturing? If not, getting ghosts may require changes to DAZ Studio so you could mark a character or object for hidden-face removal as the mesh data are being prepared to send to Iray.

Comments

  • ZyloxZylox Posts: 787

    You could try http://www.daz3d.com/pwghost although I have no idea if it will work with Iray.

  • OstadanOstadan Posts: 1,125

    Our idea of 'ghostly' is based on motion pictures.  As you observed, a 'transparent' person whose clothes hide his skin, but not the thing behind him, makes no physical sense.  I haven't heard of any better solution than doing it like films have done for a hundred years: double exposure.  It's easier for us than it was for Hollywood, though, because you can render the 'transparent' character in the complete set rather than in blackness.

  • Oso3DOso3D Posts: 15,009
    edited March 2017

    PWGhost won't work in Iray.

    Phantasm and Outline in my free shaders can help a little, but I think ultimately what Ostadan said.

    Another thing you can try is rendering someone as a fog.

     

    Post edited by Oso3D on
  • nicsttnicstt Posts: 11,715

    Apply a glass shader and try a measure of opacity as well - might work.

  • InkuboInkubo Posts: 745
    Zylox said:

    You could try http://www.daz3d.com/pwghost although I have no idea if it will work with Iray.

    pwGhost is absolutely beautiful for 3Delight. I wish it worked in Iray!

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