Mars - MOLA & HiRISE to create highly detailed terrain

[cdrose]

Hi everyone,

I'm currently working on a personal project, my aim is to re-create a highly detailed Mars. The whole planet would be nice but a large section/area would suffice as ultimately I plan on importing the finished high detailed terrain into a game engine. For now though I need to work out how to use the MOLA and HiRISE data.

I have already got the MOLA data imported into Terragen and working really well, but then came across threads on there where someone appeared to "add" in HiRISE data on top to provide the finer detail. I'm looking to re-create this and at this moment am currently stuck. I believe the HiRISE data is in a DTM format? I have downloaded and looked at different software for converting it and most mention GeoTiff? Is this the correct route?

Thanks,
Chris

[Oshyan]

You should be able to load the DTM data directly into Terragen using a Geog Heightfield shader. Have you tried it?

- Oshyan

[cdrose]

You should be able to load the DTM data directly into Terragen using a Geog Heightfield shader. Have you tried it?

- Oshyan

Oh ok that's good, no I haven't yet. So as a test I am going to try and use the ".img" file from http://www.uahirise.org/dtm/dtm.php?ID=ESP_041277_2115. Would I plug the Geog Heightfield Shader into the MOLA Shader or visa versa?

Thanks for the reply!

[Oshyan]

The MOLA shader should be *above* (before) the Geog Heightfield in the network. Network flow is from top to bottom, so shaders further down in the network are on top of or override (in some cases) the ones further up. You may need to *uncheck* georeferencing in the Geog Heightfield shader at first so you see the terrain to make sure it's working when loaded. You would need to reenable it later to get the HiRise data to show up at the correct part of the planet, and then you need to locate it with your camera. You can get a start on that part by right-clicking in the 3D preview and choosing "center on object or shader", then choose the Geog Heightfield Shader. It may stick you *inside* the planet, but hopefully you can navigate your way out without too much trouble.

- Oshyan

[cdrose]

The MOLA shader should be *above* (before) the Geog Heightfield in the network. Network flow is from top to bottom, so shaders further down in the network are on top of or override (in some cases) the ones further up. You may need to *uncheck* georeferencing in the Geog Heightfield shader at first so you see the terrain to make sure it's working when loaded. You would need to reenable it later to get the HiRise data to show up at the correct part of the planet, and then you need to locate it with your camera. You can get a start on that part by right-clicking in the 3D preview and choosing "center on object or shader", then choose the Geog Heightfield Shader. It may stick you *inside* the planet, but hopefully you can navigate your way out without too much trouble.

- Oshyan

Thanks for the great tips, I'm performing "Add Terrain" then choosing "Heightfield (load DEM)" and when I turn Georeference off it appears at the north polar point of the planet and is sunken into the ground quite far. When I turn Georeference on I lose it and can't find it on the planet. Is there any configuration settings I should setup before so that my planet more accurately represents Mars?

[Oshyan]

Yes, you can change the Radius of the planet to be Mars-equivalent (it is measured in meters, so just look up Mars radius; it is set like Earth by default). Try the "Center On Object or Shader" option I mention above to move your camera when the terrain is georeferenced...

- Oshyan

[cdrose]

Yes, you can change the Radius of the planet to be Mars-equivalent (it is measured in meters, so just look up Mars radius; it is set like Earth by default). Try the "Center On Object or Shader" option I mention above to move your camera when the terrain is georeferenced...

- Oshyan

I located the shader and when Georeferenced it is floating above the surface of the planet?

[Oshyan]

Sorry for the late reply, I didn't see your message until now. So you changed the planet radius to be Mars-equivalent, and now with georeferencing enabled, the terrain is floating? Does it look at all correct with georeferencing *disabled*? Does the georeferencing seem to actually place the terrain tile where it should go on the planet, or does it just offset it vertically? It may be that the georef data doesn't work right or isn't being interpreted correctly by Terragen because it's a different planet/radius.

- Oshyan

[cdrose]

Sorry for the late reply, I didn't see your message until now. So you changed the planet radius to be Mars-equivalent, and now with georeferencing enabled, the terrain is floating? Does it look at all correct with georeferencing *disabled*? Does the georeferencing seem to actually place the terrain tile where it should go on the planet, or does it just offset it vertically? It may be that the georef data doesn't work right or isn't being interpreted correctly by Terragen because it's a different planet/radius.

- Oshyan

Hi Oshyan,

It's OK. Yea I changed the radius to "3.397e+006" with georeferencing turned off / disabled it appears at the top pole of the planet and sinks into the planet quite far to cause distortion around the edge. When georeferencing is turned on it looks like it does move into the correct position but is far away from the surface of the planet. My main aim in using the HiRISE DEM .IMG data is to combine that with the MOLA data to export the terrain into a game engine. Trying to combine the two is proving difficult.

[Oshyan]

Hmm, once again I didn't see this reply. Strange.

Anyway, if your primary goal is to get the data into a game engine and not to render it in TG, then you may be better off with a more dedicated GIS application like GlobalMapper. The workflow might then be simplified, particularly for flexible data output.

That being said I do hope in the meantime you may have found a working approach. There is someone on the forums here who has experimented with similar setups and I think he was able to overcome some issues eventually. You can see one of his threads here (mahnmut): http://www.planetside.co.uk/forums/index.php/topic,15070.0.html
He was last active in late June, but he may respond to a private message or email.

- Oshyan

[cdrose]

Hmm, once again I didn't see this reply. Strange.

Anyway, if your primary goal is to get the data into a game engine and not to render it in TG, then you may be better off with a more dedicated GIS application like GlobalMapper. The workflow might then be simplified, particularly for flexible data output.

That being said I do hope in the meantime you may have found a working approach. There is someone on the forums here who has experimented with similar setups and I think he was able to overcome some issues eventually. You can see one of his threads here (mahnmut): http://www.planetside.co.uk/forums/index.php/topic,15070.0.html
He was last active in late June, but he may respond to a private message or email.

- Oshyan

No problem, Ok thanks for that I will contact him and see if he can help. I'm struggling with the Global Mapper software as I keep getting a crash, I think it may be because I'm using Windows 10. I will keep this thread updated with any new findings.