DAZ Studio IRAY shadow casting

Mediasylum

Is there a way to turn off shadow casting for any particular object (or per surface of an object) in a scene?

(without affecting received shadows for that object and without globally disabling shadow casting for light sources)

Richard Haseltine

Not in Photoreal mode, no - that is part of the point of Iray, simulating the way real light behaves.

Mediasylum

Too bad, it could be very useful for some assets extracted from games, which use poorly modeled decal meshes (the gap between the base mesh and it's decal is often too big so the shadow becomes quite noticeable).

Alas, no simple solution for me within a single DCC app.

Richard Haseltine

You could use a dForm or Push Modifier, with a weight map, to move the decal part.

Mediasylum

If my problem was with just one decal - I would have figure out some workaround.

But the problematic asset is a relatively large architectural assembly with hundreds of differently shaped decal meshes.

Richard Haseltine

if they are literally decals (just flat planes) and have their own materials then you could apply a push modifier with a negative offset (which will push everything "backwards"), add the weight node, clear the weight map, use the Select By>Surface group right-click option to seelct them all, and set the weight to 1. That should get you close, at least, in a few clicks.

Mediasylum

The problem is precisely that those decals are not always planes, they are roughly shaped like the surfaces they are suppose to cover.

Like in every place where floor or wall or ceiling meet there is a curved decal to mask that sharp transition and add some natural dirt.

I've attached an example, with some decals colored (it seems the walls have 2nd layer of wider decals).

 

Richard Haseltine

Push modifier might well work, since it moves the mesh along the local normal (vertex normal, I think) so they would maintain their shape.

Mediasylum

I may have better control editing those decals in some other app, which allows for collision checking while editing decals 

(tighter shrink wrapping with constrain to background meshes).

Anyway, it's not as simple solution as I was hoping to get.