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#1
Last post by Dune - Today at 02:29:45 AM
The tunnel story was fun to ask, as I knew it wouldn't be straightforward. GPT says a lot of nonsense sometimes, I'd never rely on it.
It is possible to make a tunnel like a mine shaft, but it's awkward. Bearing in mind that the surface of the planet is a thin, warpable sheet, you can use vector displacement (either within TG with some ingenious nodes, or from an outside painted vector displacement map) to bend two parts together 'underground' and let them intersect eachother. Then use a default shader's opacity slot and a rotated simple shape to make part of the intersection transparent, and you can see through the tunnel.
If you use painted shader or rotated simple shape from either side of a mountain or ridge to bend the mountainside inward, let two sides intersect, and do the same, you can have a 'normal' tunnel.
Or build one from a set of overlapping cubes, all displaced by the same fractal set.
Terragen is pretty versatile, but AI hasn't beaten it yet.
#2
Yeah, so obviously ChatGPT doesn't actually use Terragen. Several of the suggested nodes above don't even exist within Terragen. I'd have to say that probability that its answer was correct is exactly 0%.
Granted, it would be nice to be able to tunnel through a procedural terrain with some kind of boolean node, but for now I think you would have to export a portion of the terrain as a mesh, then construct your tunnel in a 3d modeling app, and import the mesh back into Terragen.
#3
Last post by raymoh - March 22, 2026, 03:38:13 PM
Recently, there have been more and more disruptions/interruptions on your server, resulting in Terragen constantly complaining that the "license has expired" or the app doesn't start at all and the website is no longer accessible. It would be great if you could get this under control again. It's getting annoying over time.
However, if this is just normal server maintenance, it would be nice if you at least communicated this.
#5
Great question. I've done some research on this in the past and hopefully this may help. Here's an example for one surface of an object exported in OBJ format and its associated MTL file.
newmtl Sidewinder_NotSmooth
Kd 0.95 0.95 0.95
Ke 1 0 1
Ka 1 1 0
Ks 0.5 1.0 1.0
Ns 500
Tr 0
d 0.5
Ni 1.123
Tf 0.5 0.2 0.8
map_Kd Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Color_1001.png
map_Ke Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Normal_1001.png
Bump Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Height_1001.png
map_Ks Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Metallic_1001.png
map_Bump Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Height_1001.png
map_Ns Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Roughness_1001.png
map_d Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Normal_1001.png
map_Pm Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Metallic_1001.png
map_Pr Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Metallic_1001.png
map_Ps Z:/Library/Images/Vehicles/Air/Sidewinder_Missile/SidewinderMissile_SubPainter_v001_Metallic_1001.png
In a PBR Metallic Roughness workflow the metalness image provides the specular information.
You'll want to assign the image associated with the MTL's map_Ks parameter to the Default shader's Metalness image parameter in Terragen. Currently Terragen does not automatically do this; but this behavior may be updated in the future. The Metalness parameter should be set to a value of 1 because all three of the Default shader's metalness parameters are multiplied together for the final value.
The Default shader automatically maps the MTL's Ks value to the Default shader's Fresnel Reflectivity parameter.
#6
Last post by Dune - March 20, 2026, 02:53:11 AM
For forced displacement you'd need a considerable amount of vertices per leaf to make it look nice. For the average leaf, bump works a lot easier and usually very nicely. Will you be so close with your camera?
Opacity should work, I would say, even then.
#7
Last post by Dune - March 20, 2026, 02:50:12 AM
OBJ's don't import completely, AFAIK. It's better to import spec (and other) maps from the default shader within the object. And save as TGO for future use.
#8
Last post by PuffnStuff - March 20, 2026, 02:15:52 AM
So... does anyone know the proper .mtl syntax to import a specular map through TG's obj importer?
TIA.
#9
Last post by PuffnStuff - March 20, 2026, 02:14:15 AM
Errr... trying to apply opacity to leaves while forcing displacement on them, rather than default or ray-traced.
#10
Last post by Stormlord - March 15, 2026, 06:10:05 AM
Nice, it looks very livid!
STORMLORD
