cgartashish Posted September 8, 2016 Share Posted September 8, 2016 Hi, I want to place a 3d object onto a real background and match the lighting. I am using PBR rendering option in Mantra. I am having a hard time to find out a shader/material that only recieves shadow and do not cast any shadow. I have tried shadow matte shader but it renders completely black. Can anyone please help me. I would also appreciate if anyone can please suggest me how to change the properties of an object as to only cast shadow or receive shadow and similar components. Thanks Quote Link to comment Share on other sites More sharing options...
carlo_c Posted September 8, 2016 Share Posted September 8, 2016 (edited) Check the alpha of the shadow matte render, the shadow should be living in there! Edited September 8, 2016 by carlo_c Quote Link to comment Share on other sites More sharing options...
cgartashish Posted September 8, 2016 Author Share Posted September 8, 2016 4 hours ago, carlo_c said: Check the alpha of the shadow matte render, the shadow should be living in there! Thanks, I found the shadow in alpha channel as you suggested, but I am still facing the same problem, in my render view and mplay, the grid with shadow matte still renders black but the shadow is present in the alpha channel. Is there any way that I can see the shadows directly in render view? Please let me know. Thanks again. Quote Link to comment Share on other sites More sharing options...
carlo_c Posted September 9, 2016 Share Posted September 9, 2016 What you'd usually want to do is render the shadow separately and comp it back in so you can fine tune it to the shot. The black rgb isn't a problem as you have the shadow in the alpha and can do whatever you need to with it in post such as grading it to match existing shadows in the plate. 1 Quote Link to comment Share on other sites More sharing options...
cgartashish Posted September 9, 2016 Author Share Posted September 9, 2016 4 hours ago, carlo_c said: What you'd usually want to do is render the shadow separately and comp it back in so you can fine tune it to the shot. The black rgb isn't a problem as you have the shadow in the alpha and can do whatever you need to with it in post such as grading it to match existing shadows in the plate. Thank you, actually I will render a separate pass/take for the shadow and use it in comp later, but just for the sake of instantly viewing the result in render view/mplay, is there a way to setup the render in such a way that it automatically renders the scene with the shadow and not just a black object for the shadow catcher. Just for viewing sake and when I am satisfied with the result then I would set up a renderer with different passes for comp. Thanks again Quote Link to comment Share on other sites More sharing options...
carlo_c Posted September 9, 2016 Share Posted September 9, 2016 (edited) I think the way I'd do that is to set up one take with the normal material and a take with the matte, then you can test away with the normal material. When you need to render out the shadow just switch takes and you're good to go. Just put this basic scene together to illustrate what I meant in case it didn't make sense shadow_matte_take.hipnc Edited September 9, 2016 by carlo_c added scene file 2 Quote Link to comment Share on other sites More sharing options...
cgartashish Posted September 24, 2016 Author Share Posted September 24, 2016 On 9/9/2016 at 0:11 PM, carlo_c said: I think the way I'd do that is to set up one take with the normal material and a take with the matte, then you can test away with the normal material. When you need to render out the shadow just switch takes and you're good to go. Just put this basic scene together to illustrate what I meant in case it didn't make sense shadow_matte_take.hipnc Thanks a lot for your help. Quote Link to comment Share on other sites More sharing options...
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