Getting Accurate dwg topo data into 3dsmax

[mean_pixel]

Disclaimer - I have never touched AutoCAD in my life.

 

I need to get accurate (relatively) topo data from a dwg file into 3dsMax8. It would be nice if I could get nice, continuous isolines to run a terrain modifier on once I get it into Max. It would also be nice if I could get all this output to quads. What I do get is isolines that triangulate badly when I apply the terrain modifier to it, and generally look fairly craptacular. I could ponder why this is the case (different isolines don't contain same number of verts, etc), but at the end of it all, I get the feeling I must be missing something. Anyone have a good defined pipeline for this? (Please include any ideas for file prepwork on the AutoCAD side, or if it's all meticulous work in 3dsmax to get good isolines for the terrain modifier.)

 

Is there any way a grayscale image (.TIN, etc) can be created from topo data in AutoCAD, then brought into 3dsmax and used as a heightmap?

 

Advanced apologies if I'm using the wrong terminology here, I'm a 3dsmax artist/animator thrust into the realm of engineers, architects, and GIS-monkeys (Apologies to any GIS folks present here. Here, relax and have a banana.. )

 

Thanks in advance,

[frank1331]

The best advice I can give you is to try Sketch-up. You can get a free download, good for like 8 hours or something. You can pull the topo into Sketch-up then save it out for Max.

[kdavenport]

mean_pixel,

 

I find that working with Terrain is like working with Loft. One of my biggest complaints about terrain is the craptastic topology that it creates. I find that I can clean it up quite a bit by editing the splines so that they have the same number of verts; the cracked-out triangulation comes from the fact that terrain has to guess how to connect the segments from spline to spline, kind of like loft and boolean. So, that's one way.

 

Another way I've found works well is to make the terrain normally and then use it to create a height map. This can be done by placing an instanced falloff map in the diffuse color and self-illumination channels (self-illumination so that the lights will not effect it) and using "Towards/Away" for the falloff type and "Local z-axis" for the falloff direction. You can then render it from the top viewport to get a start and then crop and clean it up in Photoshop. To avoid the whole self-illumination thing, you could just use the Render to Elements tab of the Render Scene dialogue to render out the diffuse color channel alone.

 

I hope this is helpful!

[mean_pixel]

frank1331:

 

I grabbed the Sketchup demo and found that the DWG topo data comes in as splines(?), which is good. I also found that there is a Sandbox terrain tool that will theoretically apply a surface to these lines, and that is also good. Unfortunately, the user reference states the tool is accessible through the draw menu, though the function doesn't appear to exist in the menu, or as an icon, which is bad. Have you ever used this function and where is it in the UI?

 

kdavenport:

 

Sometimes the data I'll be dealing with will be over a square mile in size. It may take too much time to clean up the isoline verts on a file that size to get the mesh to quad properly.

 

I agree with you, someone needs to make a better terrain modifier for 3dsmax, as I am sure other civil engineering types are dealing with the same problem. I am going to try the height map approach in a bit - it seems like a good solution given it would output clean quads, and it would give me decent control over mesh density.

 

Thanks to both of you guys for the response. This place is great.

[mean_pixel]

Ack. When I get the isolines imported into Max and attempt the terrain on a near 1 mile-squared site, it gives me the nastiest terrain I have ever seen.

 

I suppose that perhaps cleaning up the isolines so the vert count matches may be a necessity?