Tracks Pittsburgh International Race Complex LiDAR "Tech Demo" 0.2

[Ryno917]

I went ahead and made a video about it, but it's not a tutorial; it's more of a random ramble through my thoughts of how I would do it.

Had a watch through of this tonight while I was working on a couple other things. I enjoy the 'stream of consciousness' type videos; insight into the thought process is what makes a solid tutorial.

I think the biggest difference on my end is working without LIDAR, so I can rely on shrinking everything down to the say base data to ensure it's "close enough" before the manual stitching.

That being said, I really like your solidified-road-as-boolean-tool method, with the geo nodes for connecting edge verts. I'm trying something on my end now to see if I can accomplish what I'm looking for

 

[ohyeah2389]

Had a watch through of this tonight while I was working on a couple other things. I enjoy the 'stream of consciousness' type videos; insight into the thought process is what makes a solid tutorial.

I think the biggest difference on my end is working without LIDAR, so I can rely on shrinking everything down to the say base data to ensure it's "close enough" before the manual stitching.

That being said, I really like your solidified-road-as-boolean-tool method, with the geo nodes for connecting edge verts. I'm trying something on my end now to see if I can accomplish what I'm looking for

What track are you looking at that wouldn't have LiDAR?

 

[Ryno917]

What track are you looking at that wouldn't have LiDAR?

A fictional one

I've also got another semi-fictional circuit in the works, for which I have modern LiDAR for some of it, but there's a LOT of tree cover and the data isn't properly indexed to split them out, and I'm setting it in the 60s, so even then there's a lot of the LiDAR I can't use.

Based on your notes, I worked out this method which I think will work well enough for most circuits (probably pretty tedious for modern street circuits, though). I did a second version of the main track surface which is slightly narrower, and used that for the solidify that is used to boolean the alt routes out. That gives the alt route a slight overlap over the main mesh so I can shrink wrap it.

Is there a way to automatically create a vertex group of just the vertices resulting from the boolean? Like you, I prefer working parametrically but my experience is with Solidworks and OnShape, so I don't know most of the workflows in Blender to allow it.

If I could find a method to create an auto vertex group of only the vertices resulting from the boolean, then I wouldn't need the overlap.


This would be a base starting point while I'm layout out all of the roads, good enough for testing the layout to make sure it drives well before collapsing things. And then I could do the final mesh pretty easily by duplicating it all (to keep a backup copy), collapsing modifiers and joining into one object. Then I'd do a merge-by-distance to join them all, and maybe a subdivide and manual cleanup if needed. Then I'd do the physics mesh with the noise for driving feel.

I think that workflow would make sense... Probably not good enough for a street circuit with more complex intersections, but probably will be serviceable enough for typical road courses. Unfortunately it's too late to use this for my first circuit, and the second is a street circuit, but maybe I'll remember this next time

 

[ohyeah2389]

A fictional one

Oh, well yeah, duh.

Based on your notes, I worked out this method which I think will work well enough for most circuits (probably pretty tedious for modern street circuits, though). I did a second version of the main track surface which is slightly narrower, and used that for the solidify that is used to boolean the alt routes out. That gives the alt route a slight overlap over the main mesh so I can shrink wrap it.

That is not how I would do it. I remember reading somewhere that AC does not like road meshes that overlap. It might be fine for the graphical mesh, but for the physical mesh make sure each vertex connects to each vertex.

Is there a way to automatically create a vertex group of just the vertices resulting from the boolean?

No, not really, but as I showed in the terrain modifiers breakdown, you can use a Data Transfer modifier to transfer over a vertex group assigned to every vertex of the target mesh to an empty vertex group on the controlled mesh after the modifier stack using the "Projected Face Interpolated" mapping, which might or might not work.

I think that workflow would make sense... Probably not good enough for a street circuit with more complex intersections, but probably will be serviceable enough for typical road courses. Unfortunately it's too late to use this for my first circuit, and the second is a street circuit, but maybe I'll remember this next time

I don't mess with street circuits, partly because I have a phobia of modeling big buildings, but mostly because I don't want to deal with the roads and curbs and paint lines and markings and whatever.

Also, not to be rude, but I think both of us are a bit guilty of https://xyproblem.info/

 

[Ryno917]

Oh, well yeah, duh.


That is not how I would do it. I remember reading somewhere that AC does not like road meshes that overlap. It might be fine for the graphical mesh, but for the physical mesh make sure each vertex connects to each vertex.


No, not really, but as I showed in the terrain modifiers breakdown, you can use a Data Transfer modifier to transfer over a vertex group assigned to every vertex of the target mesh to an empty vertex group on the controlled mesh after the modifier stack using the "Projected Face Interpolated" mapping, which might or might not work.


I don't mess with street circuits, partly because I have a phobia of modeling big buildings, but mostly because I don't want to deal with the roads and curbs and paint lines and markings and whatever.

Also, not to be rude, but I think both of us are a bit guilty of https://xyproblem.info/

The overlap is just temporary while sorting out the layout; it'd be properly joined once it's all set


Definitely some XY problem guilt here, but I haven't ever found a half-way suitable workflow for road intersections in Blender and this is as close as I've gotten.