I've seen that phrase or something like it periodically. What is it? How do you do it? Also, would this enable me to render an image with a ground shadow, and then render it again with a background behind it?

multi-pass rendering is when you render only certain elements at a time usually foreground to background (or vice versa) then composite in a graphics program such as Photoshop. As for your other quetion, not sure what you're trying to accomplish but as I read it, you'd probably have a seam at the horizon line regardless of how you proceed. Have you considered using prop like Daz' cyclorama, RDNA's infinity cove? If your background image incorporates the gound, that could do the trick allowing use of shadows in a somewhat "realistic" manner.

I almost always render in several passes. Most of my scenes are in some environment such as a building or street, so I render with the Shadow Catcher enabled for my figure(s), then render the scene without figures. Stitch them together in Photoshop and if necessary, drop a sky behind the whole shebang. Sometimes I'll render a sky backdrop - I built a couple of simple sky shaders - and sometimes I'll use a simple gradient fill.

Basically what I'm trying to do is to use a background that has all elements in it (sky, trees, ground/water), and add a figure (unicorns), more trees, plants, props etc in front of it and have it all look like it belongs in that setting. However, I don't like the floating look. I want perspective shadows. I know I can render the figure with a ground shadow, and then render the background by itself and then put them together inside Paint Shop Pro, but I'd like to avoid doing that if it's possible. I thought this multipass rendering would be the answer.

Attached Link: http://www.renderosity.com/viewed.ez?galleryid=1140694

Render the background without the figures (save this render) then, add each figure or figures (as you hardware can handle) in and area render. Poser will add the area render on top of the previous render. Unfortunately, it tend to put in a solid line of pixels on the side and bottom (for me) so I save the first clean render and layer the other renders in on top in psp then erase the pixel lines. Thats how I got the linked image to render

Yes, that's exactly what I'm trying to accomplish! After I save that background render, do I hide the background and do the area renders with just the figure? Or do I do an area render taking into account the background too?

I left the background objects because in my render they were not much of a burden on the render. if you have lots of stuff in the background, i would suggest turning off anything that is not in the area render. just make sure you know where your shadows are falling so you get the area reanders to cover them. ya know now that i think about it im not sure you need to turn anything off after you get the background rendered. you could try rendering the background then turn everything on and area render smaller sections until you get everything else covered.

Thanks, I'll give this a try when I get back.

"so I render with the Shadow Catcher enabled for my figure" What's this then?

"so I render with the Shadow Catcher enabled for my figure" >What's this then? basicaly it is a transparent item that shadows are cast on. It allows you to put the image on top of a background of (for example) a street and have your shadows appear to be cast properly on the ground. the default p6 ground plain is a shadow catcher

The term 'Multi pass rendering' refers to rendering the light & surface details of a scene,not to specific objects. rendering light,reflection,specularity,shadows,diffuse materials,zdepth,ambient occlusion,self illumination etc,etc..all as seperate images Acadia..using this method you could render your shadow as a seperate image,this gives a lot of versatility in postworking your images there's generally no extra rendertime involved either as all these passes are generated while the main pass renders. Poser users can render multi passes using Gloworm (@ Daz)

Stonemason: It looks like a new urban set... Really interesting...

Hmmm, interesting stonemason. I've seen posts about Gloworm but haven't really paid attention to it. Is it a program that you use within Poser to render or is it an external application where you make your scene in Poser and then import it into Gloworm to render it? If it's a separate program, how much space does it take up? Are all of those images in your screenshot separate images that are put together inside your graphic program?

GlowWorm is a python program you us in poser. it outputs to files that you assemble in your graphics program.

"Are all of those images in your screenshot separate images that are put together inside your graphic program?" to follow on from Tyger, yes,everything is rendered as seperate files then brought into a paint program that supports layers..the 'light' render might be set to screen,'shadow' would be multiply etc....as they are all on seperate layers you can adjust the opacity of everything.adjust the blending. if your doing a scifi scene with lots of ambient materials..then those materials could be a 'self illumination' pass..from that you could get some nice glow effects with a simple blur. Cheers Stefan

Attached Link: http://www.poseworks.com/glowworm/

Multipass rendering (MPR) will help you in three basic ways:

1) Lower-memory renders. Breaking an image into multiple renders lessens the burden on your machine when rendering. Many users have found that they are able to render scenes that previously caused "out of memory" errors, by breaking up the render into multiple passes and then compositing them.

2) Fast changes. If you need to lighten a shadow, adjust a color or tinker with any other aspect of your image, you can make those changes very easily in Photoshop/AfterEffects/Gimp/Whatever, and not re-render. This, more than anything else, is why professionals use MPR--when the boss or the client wants a change made, you don't want to be stuck rendering; you want the fast, full quality feedback that programs like Photoshop and AfterEffects provide.

3) Special effects. MPR makes it simple to add things like glows and depth-of-field to your renders. Particularly with animations, MPR opens up all kinds of new avenues of creativity.

You can view tutorials for GlowWorm and get more info on multipass rendering from the above link.

I've put gloworm into my wishlist at Daz. Not sure when I'll be able to buy it though, but it definitly sounds like a must have.

I'm going right now to buy. I always do several separate renders so that I can composit and fuss as much as I like. But it's always one at a time. GlowWorm sounds fantastic! So I don't have to dread rendering the same scene over and over again just to get separate elements? Very cool.