renderable contour lines

[weetie]

Hi,

 

I'm trying to find a way to render contour lines on my topo model. It's a big model (an entire college campus) with 1' topo lines. I need to be able to render in 30 seconds or so because I'll be showing the model as part of a conference meeting & need to be able to pan to different locations & render the views as we're discussing the project.

 

I can't just do Renderable Spline because even setting sides to 3, no autosmooth, interpolation = 0 I still get a facecount of over 1.8 million. Takes too long to render.

 

I can't use a bitmap of the contour lines. A small bitmap makes the contours too pixellated & chunky in zoomed-in views. If I use a large bitmap the lines don't show up in a zoomed-out view.

 

I can't use Normalize Spline because the contour lines wind up crisscrossing each other.

 

I'm using Viz 6 w/mental ray. I could also use brazil, although it's not active on this machine. Does anyone know of another technique I could use? Perhaps a plugin? Is there something that would make viz render like a cad program where the contour lines would keep a fixed-pixel size rather than the way viz renders them - defining them as a multi-side tube with a real-world diameter? Or perhaps there's a technique for refining the vertex count of the contour line splines down to a resonable number without creating crisscrosses etc.?

 

Thanks for any suggestions!

[AJLynn]

I wonder whether doing this in Viz and rendering while you've got an audience there is the best way to go about doing this. Isn't there any other software you could be using? Or could you choose the views beforehand, render, then present those results? Honestly I've never even seen anybody try to render while presenting, and if you're doing it in response to people saying "go there, no, step back 5 feet" it could get ugly real quick.

 

If you could use other software and need to do this interactively I'd try it in Sketchup (use tour guide, set up page tabs for all important views, have the contour lines there from your CAD, and as you talk, click on the tabs in sequence and Sketchup will automatically pan, scan and dolly the view to go between them).

 

But the real question would be "what are you really trying to do?"

[Brian Smith]

I would have to agree with everything Andrew said but if that still doesnt work for you, why not just use a really good graphics card and use shaded mode. You're simply not going to be able to do what you want with any kind of realism...you could always use some of the VR software out there, none of which i like or would ever use btw. With a good graphics card wouldnt that give you what you want using rendered splines visible in viewport?

[weetie]

Boy, you guys respond fast!

 

Andrew - funny you should mention Sketchup...

 

That's what I was presenting in last week & my laptop overheated & shut down twice because of the huge file size. I'd created the topo in Viz & optimized the heck out of it, but between the topo object & all the contour lines, Sketchup just couldn't cope. So now I'm trying to devise a better presentation method. Figured I'd start with Viz/Max since I'm most familiar with it.

 

Essentially, I'm trying to show eye-level & aerial views of the topo w/simple mass models of buildings. Simple bitmap of streets & sidewalks on the topo, visible contour lines, buildings shown flat color & outline, or toon shaded. Simple ray-traced building shadows would be nice but I don't need any more realism than that. Your "go there, no, step back 5 feet" about sums it up. I also need to render out quick flythroughs showing travel along a road or sidewalk.

 

I think I need to look outside Viz, but that leaves so much territory to cover I'm not sure what apps to start evaluating first.

 

A better graphics card would work. Don't know if the design of the laptop would allow that. It's got such poor airflow that even though it has 3 fans it still overheats. Worth looking into, though.

[AJLynn]

Wow. Sounds like your laptop needs to be serviced. What kind is it? Did you have hardware OpenGL turned on in Sketchup? What's its video card? Were your using shadows, profile lines or any other effects that tend to slow it down? Was the laptop on a surface that prevented air flow?

 

Can you reimport the topos (just the topo lines) from cad into Sketchup and do a quick Sketchup version of the geometry?

 

The reason I keep going on Sketchup is that it's so much better for this kind of thing, since it doesn't render.

[weetie]

It's a HP laptop. Basically, it's their top of the line laptop (or so I'm told). It's got a 3.4 pentium w/HT. The graphics card is an ATI 128 mb. I don't have all the specs with me 'cause I had to ship it off to one of our other offices on Friday. We all share it. I had shadows & other effects turned off. The airflow was awful. Once I realized it was overheating I propped it up, but the internal airflow still seems sucky.

 

I initially tried to build the topo in sketchup, but the polygons involved just blew it up. I chopped the drawing up into a couple dozen section, terrained them in sketchup & grouped them together. The best method I found was to build the topo in viz, use the terrain simplification settings & optimize modifier to reduce the facecount, slice it into quadrants & import each quadrant into sketchup.

 

I agree that sketchup would be the best app for many reasons. Just wish it had more horsepower.

[manta]

Did you try using the MR contour shader...

[classix]

I am not sure if I got your problem exactly, but what about mapping the contour lines with gradient ramp. Please refer to attached image.

 

hope that helps

Marcus

 

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