Individual Object Rendering for Post Composition

[MegaPixel]

Ok guys, I'm having a great deal of Difficulty figuring out the best method for Rendering Specific Objects within a large scene for layering and composition in Photoshop for further manipulation.

 

I've tried going into the object properties and unchecking "Visible to Camera" for objects which I don't want to see however I still want them to Cast and Recieve Shadows onto the Objects which I do want to see. Wether the box is checked here or not, I can't seem to get the "now invisible objects" to still block out parts of objects I do wish to see as they would normaly - Are you confused yet?

Ok so as a last resort, I applied a Matte Shadow material to all of the objects I dont want to see. This kind of worked but I didn't get a clean isolation of what I wanted to see and I had to overide the materials in my scene which is undesirable.

 

Can someone tell me if I'm missing something or doing something wrong? I hope your not going to tell me to buy the 'Cebas' PSD Manager because I know that would do the trick for me however I'm not in a position to make purchases at the moments and their Demo only works at low res. and watermarks the images. Thank you guys - MegaPixel

[stefkeB]

matte material & render elements is the way to go, though. And it requires a lot of setup.

 

Maybe define two versions of your materials, using the same name and then replace them when needed from the material editor (e.g. wood01 as standard and wood01 as matte).

 

And learning a bit of Maxscript might help to automate this for your scene.

[nisus]

Hi Megapixel,

 

Check out the max user guide and read the part of the 'reversed dracula'-effect. You'll get some nice tutorials and tricks about objects visible to cameras or not, visible in reflection or not, etc.

 

Render elements... must be a way, but I can't help you yet. Have to figure it out for myself first.

 

rgds

 

nisus

[Chad Warner]

I've had best luck with matte shadow materials...and then use a TGA file and save with an alpha channel (or you can use the render elements option and then save the alpha channel as a seperate file)

 

If you want an object to block other objects, but still cast and receive shadows, make sure you uncheck the "opaque alpha" option, then under the shadows option, check "recieve shadows" and "affect alpha". If you use these options, the objects with this material will block out other objects, but not show up in the alpha channel, and they will still cast shadows.

 

I'm not sure if there is a way to render only specific objects as they would be seen in the scene without having to apply the matte shadow material.

 

-Chad

[MegaPixel]

If I ever figure out a good way to do this, I'm going to write a Tutorial on it. This procedure is very useful to the Design Visualization Community in Particular.

 

So far, The key seems to be in the Matte Material Element. It looks like you have the ability to add additional scene objects to your Matte from within the Elements Rollout. Now I wonder if you even need to apply the Matte Material to your scene objects at all? I also noticed that in the Render Styles Pull Down, The Place where you find Region, Cropped, Etc., there is also a Selected option. Now I'm not sure if it will Render out ONLY the selection or if it will Occlude objects that are in the Foreground. I'll let you know how that turns out.

 

[ December 19, 2003, 09:03 AM: Message edited by: MegaPixel ]

[abicalho]

Look for the new Matte Render Element in MAX 6. It should help you mask different objects.

 

I used Combustion and RPFs for Design VIZ quite a lot. It was pretty cool to have "Render Occluded" on, and then be able to mess with objects, colors, masks in Combustion for an entire animation.

 

Alexander

[MegaPixel]

Alexander,

 

Do you know if it is possible to Render Multiple Mattes in one pass by assigning different G-Buffer ID's to your objects? Right now, I have to re-render objects individually to get the Matte Element I want which requires re-rendering the whole scene again (A Painfully slow process). The Reason I asked is because I noticed that in the New Matte Elements Rollout, there is a Effects ID check box and a G-Buffer ID checkbox along with the pick additional objects option. These new options are very interesting and could possibly offer the solution we were looking for.

 

[ December 20, 2003, 10:35 PM: Message edited by: MegaPixel ]

[abicalho]

Yes, you can add many Matte Render Elements, specifying a different output file for each, and different settings.

 

Alexander

[Iain Denby]

How about selecting the specific objects and then choose 'render selected' It then renders those objects complete with shadows etc. Do the same for the blocking objects, then subtract one from the other in PS.

[abicalho]

Dibbers,

 

It won't work if you have Raytracing and if you have shadows cast from objects that were not part of the selection.

 

Alexander