Make figure drop shadows on transparent background

lasersayspew

So here's a problem: 

I've got a scene that I want to render in 2 parts that I will then combine: background and a figure in front of it. There will be several poses for the figure with the same background. So I hide the figure and render the background as a whole pic. Then I render the figure without background and once I tried I realized that I lose shadows that figure is supposed to drop. Right now figure is rendering to png and everything else is jsut transparent so I add it as a layer in photoshop. Is there a way to make the render also catch shadows on that transparent background? Kinda hard to explain, lol.

I want the image that contains the figure to also contain shadows and make those shadows transparent so that I could still slap that image as a layer. Is it possible?

2 attachments: first is a whole render to show how the scene is supposed to look after merging. Second one is background+figure rendered seperately and merged afterwards.

Richard Haseltine

https://www.daz3d.com/forums/discussion/comment/4125546/#Comment_4125546 may help

lasersayspew

Tried several tutorials on matte objects. Tried both with the wall itself and a simple plane, doesn't work. Both the plane and the wall turn invisble but they are not catching shadows for some reason. Using meshlights and spotlights.

kenshaw011267

Why not just include the 2 wall sections in the render with the character to get the shadows you want? Or is the environment not built in a way that you easily break it up?

lasersayspew

Well, the wall is 1 object, but I tried that too by hiding polygons, turns out there are also other shadows that are being cast on the walls from different objects in the scene that are not in the frame. So I either lose the shadows from the figure or the shadows from other objects. xD Guess, I'll have to render each pose as a whole scene. It takes too long + would be useful to figure out how matte works, I will need it later in other scenes. No idea what I'm doing wrong. Tried default shader for plane, tried uber shader, the moment I turn matte on it turns invisible and shadows disappear. It is still there, it blocks the view of the objects behind it but no catching shadows unfortunately.

chris-2599934

lasersayspew said:

Guess, I'll have to render each pose as a whole scene. It takes too long 

Well, one thing you can do if you can't get the whole shadow catching thing working is render the whole scene - wall and girl - once.

Then re-pose the girl, but don't render the whole scene. Select the spot render tool, go to the Tool Settings tab and choose "New Window", then select an area with the tool that includes just the girl and some of the wall behind her. It'll produce an image on a transparent background that you can superimpose on the original image to produce a new one - but probably much faster than rendering a whole new image.

 

lasersayspew

Wow! Thank you so much! I didn't even know this spotrender thing existed! xD It helps. Rendering part of the picture is 3 to 4 times faster. Awesome! Thank you again!