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Fergy

What is the difference/purpose between foreground and background rendering?

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Okay, I've searched here, and look elsewhere, but I'm not finding an answer on this.

What is the purpose of foreground rendering versus background rendering?

Is the background render mode specifically to apply to a renderworks background if a foreground rendering mode is used? I've mainly used solid black backgrounds with rendered weather effects for lighting haze.

I have always used the background render mode and left foreground as "none". What am I missing here? I'm always rendering using viewport rendering, but I'm not getting the "focus" that I'd like. I always set up my viewports using cameras. But I'm not able to control depth of field like I'd like too, nor am I getting the focus that I'd like. I don't think this is a current ability in VW, but it would be very helpful for those of us who are modeling camera views for TV or film.

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Fergy, Here is an Example (see attached). This is using Final Quality Renderworks as Background Mode and Hidden Line as Foreground. Some very nice effects can be achieved.

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When viewports were introduced, a lot of people started using a technique of stacking two viewports on top of each other. They would render the back one in OpenGL or Renderworks, and the top one in Hidden Line (maybe with a Sketch option). That way you would get the rendered objects plus the edges highlighted.

In VW 2008(?) they added the two foreground/background render options to ecah viewport. It allows you to do the above technique using a single viewport instead of two. It still has to render twice, so it is not faster than 2 viewports, but makes it easier to control.

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Gotcha. I played with it a little yesterday, and saw what was going on. I guess it's more for artistic representation than anything else. I'm spending most of my time working on as "realistic" renderings as I can get. Rendering time, crashes and out of memory errors are killing me, so I definately won't be adding another layer of rendering to the process. Unfortunately, my model has a lot of lights and light-emitting surfaces as well as reflective textures, and it's the interior of an arena with a lot of detail.

Can either of you explain the "final gather" process? I'm seeing that it doesn't use heavy processor load, nor does it use multiple processors well, at least compared to the rendering process. It seems to hang there for a long time and not appear to do much.

Peter: Just saw you're in Ashland. I'm from Eugene originally. Small world.

Edited by Fergy

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Fergy, is there any chance you could post some of your renderings? I'm always looking for inspiration in Renderworks renderings.

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I'll try to upload later tonight...these last renderings took over 8 hours so they weren't finished when I left this morning. Final Gather really slows it down, but it does seem to look much better.

Do the forum servers host images, or do I need to upload to a third-party hosting service?

Edited by Fergy

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Here are the sample renderings I've been working on. These are sheet layers with two viewports per layer. The layers are set for 150DPI, 8.5x11 so clients can print them easily. I tried to do higher resolutions, but it was way too painful.

These are for an ice show coming up in November for air on one of the networks following the football game Thanksgiving day. These are the concepts for the design. The venue is modeled accurately for the space. The scenic pieces are from actual models from the manufacturer, done in ACAD, and imported and re-modeled and textured in VW. All are colored only using lighting objects, and are either semi-transparent or white cloth surfaces.

All of these were done with render cameras in the model. The 200-level is Custom Renderworks with final gather with 16,3 as the settings. It uses simple dome at 40%, 50% as the viewport lighting option, and the renderworks background is solid black with a haze effect. There is no ambient light or directional light.

Camera 1 views has the renderworks background and the simple dome turned off. It's rendered using Final Renderworks.

Jib views are done with FInal Renderworks and the black renderworks background turned on, with haze, and the viewport lighting set to simple dome at 40%, 50%.

Please feel free to offer suggestions. I'd love to get better rendering results than I am here.

Edited by Fergy

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Hi Fergy,

I see that your event has passed. I hope it went well.

As this is a topic that I have a special interest in, I am logging my findings here. The question about foreground/background renders has been answered, so I won't address it.

Final Gather

For our purposes, Final Gather (FG) doesn't give enough bang for the buck; the rendering times are ridiculous and there's little effect. In a small room with only a couple of lights, FG can give some really nice results because it deals with bounced and scattered light. FG will compute the ambient light, creating very realistic-looking lighting, so you can light whole a room by pointing a single instrument at the ceiling. In situations like ours, with large rooms and few large, light-colored, reflective surfaces, FG makes very little difference in the final product. I leave it turned off and save _days_ of rendering time. If I need ambient bounce, I'll fake it with another light. The aded benefit here is that I have control over what gets lit and what doesn't.

Below the following images, I have attached screengrabs of the custom Renderworks settings that I have been using. Even the most complex scenes (100s of lights) are rendering in minutes ( < 10 min with (8) 2.26GHz cores ). The results are actually really good:

Dolly.jpg

Depth of field in the above image was done in Photoshop.

Camera-2.jpg

Camera-3.jpg

jib.jpg

Yes, the floor truss has no fill. D'oh!

I have seen some anomalies with lit haze buildup. If anyone has thoughts on that, I'd appreciate input.

Edited by S. Robinson

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