How to just an object in renderoutput

[DANIELE_CASAROLA]

Hi everyone!

With the ObjID renderelement I can assign a constant color to an object in the way that then in photoshop I can select it separetly and work on it.
I have to do a looot of render of the different objects of an interior, so I really like to avoid the photoshop step in which I use ObjID image to select it...
It's possible to have a sort of "Region Render" by objet in Vray? In the way that in the output image it's all black (or better trasnparent) expect for the object I working on?
So I can easily and fast save a .png file with the rendered object alone.

Thanks a lot!

[joconnell]

Use the multimatte element so you can make yourself a really nice selection mask for each of the objects in the scene - it's the cleanest way to get a good edge. Here's a run down of some options - http://www.pixelab.be/blog/2009/09/28/masks1/

[joconnell]

And another - http://cg.tutsplus.com/tutorials/cha...-in-photoshop/

[DANIELE_CASAROLA]

thank you very very much Joconnell for the info.
Anyway using the "Multimatte" renderelement I have anyway to work in photoshop, while I'd like to bypass that step, 'cause I should do it a lot of time for all objects, while it could be better to have directly in the vrayframe buffer just only the rendered object.

And also... I don't want to render each time part of the scene I'm not interest to... I lose time... I could use a "rectangular region render" but you know... even if I make a really little rectangular render region there are always buckets that render parts outside the object, because the object it's not a box

I'd simply looking for a solution to gain time.

[joconnell]

There's nothing currently - the objectSelect element kind of does what you want but it'll still do a main render with the pixels outside the object you want. It's been asked for as a feature but pop a note into the wishlist forum.

[wxyz]

Would PSD Manager http://www.google.com/url?sa=t&rct=j...qgxnVwMIG0cOsg
do the job?

[DANIELE_CASAROLA]

Yes PSD Manager helps

Thanks everybody!

[Slazzo]

You could use the environment as a matte and Affect Alpha -1, where only your object remains with Alpha on image.

Or you could use the VrayExtraTexture as a separate mask for your object, use a white vraycolor in texmap and just include the object or group of objects, you will get a black mask where only the included objects will be white and antialiased, but I'm not sure how it works with alpha and transparency, but if the object is solid you can use the mask as alpha.

As a trick, when you have to re-render a lot of times some particular parts or objects in image or animation, you can get away by using vrayspherefade if it fits your region, it will return an image with alpha and fadeout borders, is an amazing tool.

[DANIELE_CASAROLA]

thank you very very much for everything.

Useful info, I need to ask you another question, maybe it's not the very right place but it's linked to what I've posted.

Tried both VrayExtraTex+VrayColor and MultiMatteElement (I'm not sure how to use it in photoshop, just tried with "Selec Color Range"), and in both cases I have segmented white edge around the rendered object.
Which is the best way to avoid that (3dsmax+Vray side procedure and Photoshop Procedure)

Basically I have a simple wihte material assigned to the furniter for the base render, and different wood material to put on top of it.

Thank you

[joconnell]

With the multimatte you'll get perfect edges - what you need to do is make the multimatte the top layer in photoshop so nothing else is visible, go into your channels tab and then ctrl + click on the channel of the object you want to select - because it's using pure red green and blue channels, you'll get perfect anti aliasing as a selection.

[DANIELE_CASAROLA]

Thank you very very much for the support!

All solved

Good Job!