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james120479
08-04-2010, 11:14 AM
Hi,

I was hoping someone might be able to help me hopefully with a small query. I'm working on producing a montage which involves placeing a 3D model onto an existing photo. The model is quite simple but i'm having problems getting the finish to look 'realistic'.

I have used Daylight system and an hdr (not of the site) to light it and some fairly simple composite maps for the concrete and ramps. I've taken some shots from site at different exposures and will be looking to create an HDR of the actual site this afternoon... although i'm not sure the hdr will make much of a difference as there's nothing in the scene to reflect the light.

Looking at the image does anyone know where I might be going wrong or what settings I might need to pay attention to to improve the look? Any help greatly received

Thanks
James

lazzhar
08-04-2010, 05:10 PM
Don't you have a larger version? I can barely see what you added there.

sundialsvc4
08-05-2010, 02:14 AM
"Shadows are everything!"

Specifically, "edge shadows."

'Anywhere reality ends and CG begins," there must be "an edge-defining shadow." Therefore, this shadow becomes (perhaps...) your single most important obstacle to "realism."

Three things must coincide exactly:
The lighting upon the "real" object. The lighting upon the "virtual" object (that is, after all, supposed to be occupying the same space!) The lighting upon the shadow between them.

james120479
08-05-2010, 07:59 AM
Thanks for your replies, i've attached a bigger version so hopefully you can see this better... sorry.

Sundialsvc4, I think that's where i'm having my problems, certainly with matching the type of light with the photo and because of the nature of the scene the 3d model literally 'sits' on the ground casting few shadows, plus the time of day of the photo (13:20) means few casting shadows.

kanooshka
08-05-2010, 12:53 PM
One of the biggest things to note is the intensity and color of the skylight on the plate vs the composite. Here are my suggestions:

1. It's a little after noon so the sun is close to being directly overhead.
2. It's such a bright sunny day that the skylight is not very visible at all, notice the very
dark shadows from the tree, tone down the skylight a lot.
3. For the specular highlights you can still see some color on the leaves of the tree, they're not completely blown out to white. This can transfer into the composite by toning down the spec just a little.

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