Author Topic: It was an easy task in 2006 to modify shadows in Max...  (Read 1512 times)

2022-01-20, 14:22:18

orsobubu

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As a former old Max user (standard  renderer, version 8, circa 2006), I was discussing with a friend of mine, an unsophisticated Corona user, about how simple it was - at that time - to modify shadow colors using render elements and an alpha channel; I pointed out to him that in order to insert the render of a building, made with a white sun (so no hdri), in a photograph with blue ambient light, he would at least have to retouch the color of the shadows in photoshop. Having answered that he doesn't know a method to do it, I searched a bit in this forum, and it seems to me that there are functions called render pass, shadow catcher, vfb, cshading_shadows, etc but can be used only on direct shadows; moreover it would seem to be an evolving topic in time and I can't understand the current state of possibilities. Could you give me a tip or direct me to some recent article or other media on the issue?

2022-01-24, 16:26:46
Reply #1

piotrus3333

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if all you need is adjusting colours why not just use the LightMix? also an easy task since 2016.
Marcin Piotrowski
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2022-01-28, 11:00:25
Reply #2

orsobubu

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Hi Marcin, really thankyou for the kind reply, as I said I don't know Corona, I posted a question for a friend, so she tried your suggestion modifying the color of lightmix-Cshadingshadows channel, then importing it in photoshop as a layer over the original one, then invert-subtract-opacity10%, as she found in a tutorial, and the result is a slightly better image (but a bit more noisy), but it is far from my method I used twenty years ago with standard max renderer working on the shadow element, where I could easily and radically change only the direct shadows color. Here, she obtained only a very very pale, subtle blue tinting of the FULL image (areas in direct sun light included) and if she lows the layer transparency, the image gets very dark and noisy all across the board. I think the problem is the difficulty to isolate GI ambient shadows, absent in my old Max version. Maybe the right approach is to use hdri, or modify the original sun's or ambient shadows color instead of working with postproduction?

2022-01-28, 11:36:50
Reply #3

piotrus3333

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I meant LightMix in Corona Image Editor:
- try this before PS. if the setup is daylight - just add more colour to the sky to change the shadows.

Marcin Piotrowski
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2022-01-28, 13:45:58
Reply #4

piotrus3333

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in case you need to be able to do it in post 2006-style it is:

beauty+(CShading_Shadows*colour)
Marcin Piotrowski
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2022-01-28, 14:04:53
Reply #5

piotrus3333

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but LightMix is the way to go with it. in corona or in post, whatever is convenient. 2010-style (or 2011 maybe)..

(I have to note I'm assuming you are going for something realistic as you mentioned matching to photo)

Marcin Piotrowski
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2022-01-29, 23:16:33
Reply #6

orsobubu

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Marcin, my friend is studying your posts... many thanks, I'll keep you updated!!