3d Topographic map. Start from map or start from 3d terrain?

Alex_J

Goal: Make a realistic 3d map that can be traversed with map/compass orienteering methods. Does not need to conform to a real world location necessarily. 

Problem: I can pull heightmaps from online and make terrain from that easy enough. But, then how to derive an accurate topographical from that? There might be some way I can read elevation change and convert that into a map. Anybody got an idea? 


Another idea is start from a real world topo map, and then try to get height data to match that. But the only height map extractors I know of do not have way for typing in precise coordinates. Anybody know of some tools to get precise heightmaps?




Thanks!

Eric Chadwick

DEM files have precise height data, created from satellite scans.

What 3d software do you want/plan to use?

If you have the model already, you could create a simple shader to UV height lines using a sideways projection. 

If you use real-world units, it would be trivial to add regular measured topo lines. 

Alex_J

It would be great if I can use Maya as I already know it @Eric Chadwick . 

I'll google DEM files, never heard of that. 

About getting topo lines from a 3d mesh, yeah I figure that isn't so hard to do. I probably need some programmer to help me but that's fine. But I got to get this onto a texture and the scale has to be correct so that you can use this map with a simulated compass and accurately travel in a game world. For simplicity, grid north and magnetic north have no deviation. 

It's maybe not such a big task to make the scale between map and world correct? I just got to think it through. I suppose in digital realm I can forego the math and just make the map literally the same size as terrain, set my grid squares to actual unit size, and then just scale the whole thing back down. Is that what you mean?

Eric Chadwick

Yes except no need to scale down, the game engine will handle it just fine.

Which engine?

Alex_J

Unity. 


thanks for help btw @Eric Chadwick 

Eric Chadwick

Did you search? Came across this searching "unity topo terrain"

https://answers.unity.com/questions/788782/turn-a-terrain-into-a-contoured-map.html

https://forum.unity.com/threads/real-world-topographical-data-for-terrain-height-map.167193/

Eric Chadwick

Also this "unity topographical shader"

https://www.reddit.com/r/Unity3D/comments/4kfiks/topographical_map_shader/

Alex_J

I searched, but apparently pretty poorly, haha. I was probably way to specific in my wording. This shader graph is more than I could ask for. Problem solved. 

Thanks!

Eric Chadwick

Happy to help. Let us know how it turns out!

Alex_J

will do. I just starting preliminary stuff, but won't start production for a few more weeks. I make a thread about the game then. Pretty excited to get this map made, I think it will be pretty cool. something I wanted to do in a game for a long time.

Alex_J

I ended up getting good results and an efficient overall workflow from World Machine. The only downside is that I don't have precision to select each 10m interval. For practical considerations, that is okay. So long as the intervals are consistent we can accurately use them.

For anybody doing something similar, I had started by following advice from an old World Machine forums thread about the same subject. But I think some of the devices have changed a bit, and overall the device setup seemed kind of convoluted to me. I couldn't get good results.

I simplified it a bit then. USe a terrace device, set it to sharp. Then a select slope, and finally a colorize. Just play with the terrace device values and the slope values to get good, solid lines. For quick building, I disable all devices like erosion until I got the lines figured out, because the viewport resolution isn't good enough until you build.

throttlekitty

This might be too little too late, but I just remembered you can use Maya's Toon lines to generate curves at the steps in height. With your terrain mesh and a flat plane, the toon shader will make dynamic curves at the intersection.

Alex_J

@throttlekitty i am gonna try that out because i would like to have precise 10m intervals for sake of authenticity, and i think that will be easy to setup.

I manage this with world machine, and that's not bad because then whenever i go and edit the heightmaps i can output the contour lines along with it. so its pretty tidy workflow. The only thing bothers me is that i don't have that precise control over the intervals.

Alex_J

Just gonna close this out here with my final solution. I tried @throttlekitty advice in maya, but unfortunately i gotta use Maya LT as this is work I will be selling, and I don't have access to those shaders in LT.

I looked into both shaders built with Amplify and scripts to get the end result, but what ended up making most sense was World Machine since I am already building the terrain in it. The process here is very simple but I'll post it just in case any other newbs have similar question:

And here was a good idea I thought of too late. Connect that colorizer back to your scene view to get nice validation of the contour lines accuracy and spacing.