adding projector map to daylight system

[Dave Buckley]

is there a way to do this? on an interior i want to make it look like the sun is shining through trees to make the shadows more interesting (usually done with shadow map/projection, however i'm using daylight system and don't have an option to place a map anywhere

[WAcky]

Can you just map an opacity map onto a plane and place them outside the window? Make them invisible to the camera if need be.

[Dave Buckley]

yep i could indeed do that, i just wondered if there was any way of adding the map to the daylight system.

 

i guess i'll stick with the opacity map, its essentially the same thing

[Crazy Homeless Guy]

I typically use geometry, and make it not visible to camera and depending on the situation, reflection/refraction. This way renders fast.

 

The opacity map or cut out map on a plane would work, but there is potential for a huge hit on rendering time.

 

The fastest option might be a combination of the two. Take a tree alpha channel into Illustrator, and auto trace the outline so that you have a vector file. Bring that back into Max, and make it not visible to camera or reflections/refractions. now position it so it casts shadows where you need it to be.

 

Depending on the situation, the plane may need to be tilted to produce the most believable results. Then again, if you have a 3d tree ready to go, dropping it in front of the window and make it non renderable to camera and reflection/refraction will only take a couple of minutes.

[Dave Buckley]

cheers guys, a nice few tips here to add to my list of err . . . tips?

[dpcaltdcah]

to get rpc trees to cast shadows we used to use a target directional light with a projector map under advanced effects. If you make the intensity multiplier -1 (or any negative value), it basically makes negative light meaning it only casts your shadows without adding any regular light to your scene. does that make sense? you could put that roughly where the sun in your daylight system is...

 

to get the projector map, render a tree from the vantage point of that light and turn that into an alpha image. the advantage of this is in the end you don't have to have any extra gemetry in your scene.