Isolating a room in a house (quick inivisibility?)

[davision]

I need to isolate a few rooms in a house. They are created as separate geometry so they can be treated separately from other pieces of the model fairly easily.

My problem is that I'd like to isolate the rooms by "ghosting" back the rest of the house so the isolated room is full color and everything else is partially transparent -- or maybe has an "x-ray" material where the front faces are more transparent than the sides.

Rendering such an 'xray' along with the full-rendered isolated room makes for long render times. I'm trying to develop some sort of "trick" to speed it up but so far nothing is 'clicking'.

I know that I can get very fast renders if I ignore lights and use an Override xray material for the entire house. Also even with lights ignored entirely, an xray material or just vray object properties set at alpha of .1 will render super fast -- and then I can use the alpha channel as a ghosted house.

The problem comes in when I'm thinking about how to composite the full-color isolated room. If I put it behind the ghost house it will look weird because there will be too many layers in front of it -- and if comp it in front of the ghost house it will look "glued on".

Anyone have any tips on how I can do this in an efficient manner? By the way, this animation is not using GI (at least not at present) so I don't have to deal with the added complexities of that.

[Fermi]

Have you tried in Curve Editor (track tiew) adding a visibility track for the objects that appear/disappear with full control of how and when they do it?

Fermí

[ene.xis]

if u need such a thing asap the only thing it ocurs to me at the moment would be to render 2 separate passes. 1 the room only, all the other geometry hided. 2 everything else and hide the room (no need, but...)
then comp the 2 together and adjust the transperency of the 2nd...

thats quick, dull and dirty..but i suppose it works fine

[glyph]

why not render "house layers" - so in Photoshop you have the xray stuff that is in front on one layer, the fully visible stuff in the middle and the xray stuff that goes behind in another layer - then you can adjust each layer separately - and if needed set object alphas etc - but tricky if this is for animation!

[SnipeyX]

FYI, In my experiecne V-Ray doesn't always like usage of the visibility track, i've seen others talk about issues with it online also. I'd suggest comping in layers also.

[vlado]

FYI, In my experiecne V-Ray doesn't always like usage of the visibility track, i've seen others talk about issues with it online also. I'd suggest comping in layers also.

This is because V-Ray will treat semi-visible objects as semi-transparent ones, and this leads to a big slowdown. It may also not be the effect that you need (e.g. typically you don't want to see inside walls etc). So compositing this is probably the best thing to do.

Best regards,
Vlado

[davision]

Thanks all. In the interest of speed, I took the low-brow way and rendered a complete pass of the whole house and then a pass with just the isolated room -- and faded out the whole house render in Post.

It's not as pretty as it could be -- but it does the job.

By the way Vlado -- is it possible for Vray (2.0) to have an option where the visibility track acts more like a fader and not a semi-transparent control?

[dbuchhofer]

the 5 minutes of waiting for my light cache to finish on a square seems to say that visibility tracks and light cache are still not playing together nicely also! :P