Render elements only without render whole image?

[Mats_O]

Is that possible? Some elements would probably hard to render without rendering it all, but some would be really helpful to be able to render out quickly, such as z-depth, alpha, multimatte etc.

[tct70]

No, I believe that elements are a bi-product of the main render and cannot be produced on their own.

[Mats_O]

No, I believe that elements are a bi-product of the main render and cannot be produced on their own.

But things like mattes that not depend upon shading, wouldn´t that be possible to render separately?

[tct70]

Many people create a separate copy of the scene to quickly produce mattes. These then cease to be render elements.

[chrisjacks21]

If I need further render elements after I have rendered my frames, I do this by globalling turning off lights, GI, maps, reflections & glossies to render elements - usually renders pretty quick then

[Mats_O]

Yes, these methods are pretty good workarounds that I also use, but wouldn´t it great to have the possibility to quickly generate a mask for a single object for example.

[panthon]

Yes, these methods are pretty good workarounds that I also use, but wouldn´t it great to have the possibility to quickly generate a mask for a single object for example.

Multimatte element will let u do that.

[Mats_O]

Multimatte element will let u do that.

Yes, but not without rendering the scene itself, or have I missed something? (Hope so...)

[rivoli]

Yes, but not without rendering the scene itself, or have I missed something? (Hope so...)

nope, you didn't miss anything. render elements are generated while rendering the scene, as vlado once put it: side effects of a rendering. so it's not possible to output a single element without rendering the whole thing.

[panthon]

You can always use Wirecolor; this way u don't have to plan which objects will need to be masked, u just have a mask for all and each object and decide in postproduction what you want to do with them.

Nevertheless, I would say it's better planning what you are gonna do, before hitting render. If u really need to extract some elements AFTER the render, the only way is following the advice others have given you: disable most things, like glossies, reflections, etc, and then the render will be much quicker.

[instinct]

mind you that wirecolor is not nearly as exact as MultiMatte (beeing perfect red/gree/blue channel mattes)

[panthon]

mind you that wirecolor is not nearly as exact as MultiMatte (beeing perfect red/gree/blue channel mattes)

That's true, but if you are on a tight deadline and have no time to rerender, wirecolor can let u select "any" object in post, even if you didnt plan to (eg when that friendly client makes you change something u shouldnt be changing). You just need to be careful polishing the edges, while when using multimatte, it's much more straightforward.

Anyway, it helps to automate the creation of distinctive wirecolors to be fully usable. The greater the difference between each color, the easier it will be for you to pull a matte from them.

Sometimes it has been a lifesaver for me.

[pg1]

http://www.scriptspot.com/3ds-max/rendermask
one of the best scripts I have for getting out quick mattes

http://www.tepavicharov.com/scripts/...sk_preview.avi

can be slow on scenes with lots of object so I usually save a new scene called blahblah_matte.max and delete any objects I dont need

[Mats_O]

http://www.scriptspot.com/3ds-max/rendermask
one of the best scripts I have for getting out quick mattes

http://www.tepavicharov.com/scripts/...sk_preview.avi

can be slow on scenes with lots of object so I usually save a new scene called blahblah_matte.max and delete any objects I dont need

Thanks! That script will make my life a lot easier!
And the possibility to randomly assign wirecolors is a great feature.

I am doing a lot of design-viz and all images need some post in PS. It is not only about planning, sometimes I just need to tweak the color of a tiny detail in post, and the ability to generate a good mask is essential to me. This is hard to plan ahead since a scene might be made of 200 different objects, and the multimatte for example can make a mask for only three of them...