Blending real shadows with cg shadows

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
Old 10 October 2012   #1
Blending real shadows with cg shadows

Hi everyone,

I'm currently working on my demoreel, but I came across a problem, that I couldn't find a solution for. I have this tracked video sequence: footage
I plan to put a chainsaw on top of the table, but the cast shadows of the chainsaw would overlap with the real shadows on the wall behind the table, resulting in a doubled shadow.
I've already found this on the web: link
The problem is, that he uses a fixed perspective with a slight camera tilt. This allows him to use one big image, stitched together in Photoshop, that shows a complete shadowed backplate ( link ). here is a link to the complete video with breakdowns: video+breakdowns However, this won't work for me, because my camera moves around the scene and I can't just build one large shadowed backplate.
The other thing I found is this thread: link . I played around with the files he provided and tried to apply his workflow to my footage, but to be honest, I didn't fully understood this method and the attached images in Per-Anders post don't really look as good as I was hoping for (lot's of artifacts in the shadows). Also, it's a still image and not a sequence.

Btw, I work with nuke, but I'would be thankful for any answers, even if it's for a different software. You can also see the first part of my demoreel here: reel WIP . But I will propably post this again in the WIP/critiques section.

Thank's for any info/help on this!
 
Old 10 October 2012   #2
No ideas ? anyone ? well, I'll have to use a mask then... Not sure if this will work out
 
Old 10 October 2012   #3
You could probably crank the contrast up on a plate of this, garbage mask, and use a luma key and blur it a little, and use it as a mask, instead of doing it by hand.
 
Old 12 December 2012   #4
Thank's Ephisus, and sorry for the late response! I managed to solve the problem with the keylight-keyer in nuke, but your answer has sent me in the right direction. (I had no clue about keying before this project...)
Here is a link to the final video (it comes right behind the Aston Martin part):
https://vimeo.com/55108171
 
Old 12 December 2012   #5
Thread automatically closed

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 03:12 AM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.