Modeling road network on an uneven terrain

[pradipta]

Hi,

 

i would like to ask a very common question on modeling road network on uneven terrain. I use 3dsmax and am facing a problem in aligning roads, curbs on a land which is generated from a terrain data.

 

I attached a screen shot of a portion of the land form and would like to know the best possible way to add roads/curbs as on the surface.

 

Would like to hear some comments, thanks in advance for guidance

[Jonathan Sanchez]

Hey Pra

Check out the "conform compound" function in 3ds.

[David Arbogast]

I like to draw my roads as a 2d shape (either in Max or AutoCAD), extrude them, and then use a standard boolean (set to cut). Convert the boolean to a editable poly and detach the road from the terrain. Then select the road and in border mode select the outside edge, go to edge mode (with perimeter edges still selected) and use "Create Shape From Selection" (using linear segments), which give you the path needed to Sweep a curb.

 

Also this script looks promising for this sort of work: Ant-Stitcher

[pradipta]

Hi Sancheuz and David,

 

@Sancheuz, I tried using conform and shape merge tool both in 3dsmax, but the terrain mesh is just too crude and huge to work on that. Every time I tried to use those two above tool, it didnt work. I also had to refine the mesh by removing broken vertices, double edges etc but still it didnt work.

 

@David, I tried using booleran, but 3dsmax crashed couple of time before I stopped using that. Its because the mesh is around more than 1 million polys. The Anti-stitcher looks nice, I will see if I can use this effectively on the terrain.I even tried with Glue plugin, but it failed as well.

[Brodie Geers]

What's the final product? Does the site model really have to be that detailed AND large? Could you do without one of those characteristics? With the amount of detail on the model maybe you could even just create a custom texture in Photoshop and lay it on there.

 

-Brodie

[pradipta]

Hi Brodie,

 

The texture will not work in this case since I will be requiring to do close eye level shots showing the road network and curbs in detail. And the mesh is just too crude and large to manipulate. And none of the tools like boolean, conform is working, is it like these tool doesnt work when the mesh is too large?

[Brodie Geers]

I'm not a Max guru but there do seem to be issues running these sorts of things on such large meshes. I think one way or another you need to clean up that mesh before you go any further. If you're doing detail views there's no reason to have such detail on such a huge scale, right? Are you doing detail views and overall views?

 

I'm not sure what the best way is to clean up that mesh. My first thought would be to turn that mesh into a black/white displacement map - maybe using a z-depth pass from a Top view. Then I'd create a plane of the same dimensions of your mesh subdivided as much or as little as you'd like. Then place a displacement modifier on that plane using your b/w map. That would give you a nice clean mesh with a poly count as much or as little as you like/need. You'd be in a better position to trying Boolean operations at that point.

 

-Brodie

[Scott Schroeder]

You'll need a clean mesh (nice quads) to stitch your road. From your preview image, it looks like a really dirty mesh.

 

First, before anything, run the populate terrain script from scriptspot: http://www.scriptspot.com/3ds-max/scripts/populate-terrain. This will clean up your mesh and give you a pretty decent mesh to do stitching on. Glue may work better on this mesh as well since it'll be much cleaner.

[David Arbogast]

Pradipta, If you're mesh is too large for booleans to work, then there is a very simple work-around: In polygon subobject mode select the terrain polys that are in the immediate context of the road(s) and detach them as a separate object. This will give you a significantly smaller/less complex model to work with. You can perform your operations (whether boolean or glue) and when you're done you can reattach the mesh and re-weld the vertices.

 

In short, if you're working on huge-poly meshes and are having issues with it being too big, then it's a simple matter of managing the large mesh by breaking off more manageable smaller pieces; there's no reason why the mesh has to stay intact throughout your modeling process.

 

Hope that helps!

[Jonathan]

You could use a subdivided plane using the CONFORM tool to align to your dirty and high poly mesh, then if you want, bake a normals map of the high poly to the low. Bingo..

[marius e]

Hi Pradipta

 

Unfortunately I am a bit busy and can explain to much, but first clean up that mesh (follow the links provided), this is a great way of fixing those crappy terains generated into a clean proper mesh that one can work with. I also use - Glue- from Itoo software to glue those road lines etc to follow a certain shape of the terrain then use those line to cut into the terrain for roads etc.

 

Hope it helps somewhat!

 

 

 

[marius e]

You'll need a clean mesh (nice quads) to stitch your road. From your preview image, it looks like a really dirty mesh.

 

First, before anything, run the populate terrain script from scriptspot: http://www.scriptspot.com/3ds-max/scripts/populate-terrain. This will clean up your mesh and give you a pretty decent mesh to do stitching on. Glue may work better on this mesh as well since it'll be much cleaner.

 

 

Just used the tool now, very slick!