Can you use custom objects in place of planets?

[eapilot]

I am looking for a way to make a planet with very dramatic macro terrain that a height map displacement will not work, like a really giant crater. Can you swap the planet with a hi-poly object? and how hi poly of a mesh can Terragen handle well? Here are some extreme examples from films.

Another question is how do you properly plugin texture maps in Terragen's conventional surface shader?  I'm assuming it uses an older specular/glossiness map (white being glossy) instead of Disney or Unreal's metal/roughness setup? However, there are specular and roughness inputs.

Any help will be greatly appreciated,
Ethan

[Dune]

I'd go for a sphere/planet. Quickly tried a bit extreme displacement (but didn't render it on this slow machine). How is this for you?

[Oshyan]

You can do very extreme displacement, as long as the source of your displacement shapes is constructed well. If you need really specific shapes you could look at doing Vector Displacement. However keep in mind the atmosphere will not conform to the shape of the displacement, it will remain spherical.

If you did want to use an object instead of a planet, that's not really possible as you can't attach an atmosphere to an arbitrary object, but you *could* load the object where the planet should be, then turn off terrain rendering but keep atmosphere for the base planet. Again it will be a spherical atmosphere, that's all that is available at the moment, but it could enclose your object, at least. Terragen can load quite high poly objects just fine.

- Oshyan

[eapilot]

You can do very extreme displacement, as long as the source of your displacement shapes is constructed well. If you need really specific shapes you could look at doing Vector Displacement. However keep in mind the atmosphere will not conform to the shape of the displacement, it will remain spherical.

If you did want to use an object instead of a planet, that's not really possible as you can't attach an atmosphere to an arbitrary object, but you *could* load the object where the planet should be, then turn off terrain rendering but keep the atmosphere for the base planet. Again it will be a spherical atmosphere, that's all that is available at the moment, but it could enclose your object, at least. Terragen can load quite high poly objects just fine.

- Oshyan

Extreme displacement may work on some cases but the latter method will be more accurate.  Again, Is there a polycount limit that would really increase render times?  And how would you hide the terrain?  Is it placing the surface and fractal nodes in a group and hiding it in the render layer?  Spherical Atmosphere is fine.  I really want to keep the global clouds, with a custom terrain. 

I will also check out the displacement file.

I also had a question about Terragen materials and their specular and roughness maps.  I'm sure that this has been discussed before but I couldn't find a good thread that explained it.

Thanks!

[Oshyan]

There is no polycount limit, it depends more on your RAM. I would just avoid any use of the Wireframe or Shaded preview modes in the regular 3D preview. The RTP should handle high poly geometry like a champ. And rendering will be fine with all but the most crazy poly counts. To give you an idea, this is a 6.2 million tri object from Kadri Ozel used in the VR Challenge. It took about 1m15s to load the 810mb object file (loading over a network, not a local SSD, so that may have a lot to do with the time) and used about 2GB of RAM. Once loaded, however, it switched into RTP without a problem, and was fully interactive. Even the new path traced RTP mode (in Frontier builds) worked well.

A render with just the object was about 20 seconds, and with atmosphere and terrain, 32 seconds.
[attach=1][attach=2]

Obviously all just basic, default scene, but that gives you an idea of what rendering just the object alone takes vs. elements like atmosphere.

Similar result with this 16.35 million tri untextured apartment model from Slashcube. 1m4s in this render from above at 1080p. Basically Terragen is quite efficient at LoD for rendering.
[attach=3]

And in case it doesn't make sense why this object has such heavy geometry, here's a view from inside one of the rooms, the smooth curtains probably contribute a good amount. 1m57s render.
[attach=4]

- Oshyan

[eapilot]

Thanks for the reply!