Using and Controlling MOLA data

[mamoru]

Hey folks. Apologies for kind of barging in and just posting, especially as such a new TG2 user, and further apologies if my questions simply merit a "RTFM!" response or a "STFU n00b!" response. I've done my best to explore and do things, but I can't help but wonder if there is an easier way or at least more intuitive way to do what I am trying to do. The manuals and tutorials, Google, and even a Forum search, as well as just playing in the application itself, have not yet answered my questions.

My interest in Terragen2 is (for the time being) for a very specific purpose: to use MOLA data and eventually perhaps even HiRISE data to render accurate scenes of Mars. My main motivation for this is purely hobby based -- I am a big fan of Mars (mainly from reading Kim Stanley Robinson's Mars Trilogy - Red Mars, Green Mars, Blue Mars) and I want to see for myself and show others some of the places on that planet that currently I have only imagined or seen from above (like the mind blowing HiRISE pictures). When I was told that Terragen2 would be just the tool for this, I got very excited. However I haven't made a lot of progress and I would like some advice.

So, I've managed to set the size of the Planet object to the appropriate radius and to load the MOLA data, no problem. I have loaded both the 64ppd and 128ppd data sets, with the idea that I use the 64ppd set for setting up the scene I want (i.e. getting the camera to the right place, setting the FOV as I'd like it, setting up the lighting and atmosphere, etc), and then switch to the 128ppd set for final set-up of shaders and rendering, since it is so slow to work with. This idea seems to work in principal, as can be see with these two very basic, untextured test renders of the same scene (of some random location on Mars): 64ppd and 128ppd. So, I'm happy with the idea. However, my questions arise from how the data is being used.

I'm having a hard time trying to find and then get the camera to locations on the planet that I would like to render. No offense, but camera controls become horrendous the further away from the origin it gets, and it becomes outright frustrating to work with when a significant distance around a planet. So, my questions...

1.) How is the MOLA data being applied to the Planet object in TG2? i.e. What is 0,0,0 with relation to the MOLA data? Is it the north pole? Is it Martian 0º,0º at datum? At the surface? Something else? Since there is no latitude/longitude grid on the planet, it is easy to get lost. EDIT: After further playing, this does appear to be over or very close to the North Pole. Which is kind of useless with regards to the "compass", as going "north" should be meaningless from this position. Hmmmm... Is there any way to control this (such as in my question #3)?

2.) If I know the Martian latitude and longitude of a feature or area that I wish to render, is there any way to easily translate that to TG2's coordinate system to get the camera to that position without having to fly "into orbit" and perform an Eyeball mk.I search?

3.) Better yet, is there any way to set an arbitrary point in the MOLA data (preferably a latitude, longitude, and altitude above datum or above the set planetary radius) as the 0,0,0 in Terragen so that I can work with locations without having to spend so much time trying to fly around and find them, and then deal with the frustration of unintuitive perspective controls?

I guess, in short, is there any easy way when working with MOLA data to find and position the camera at any arbitrary point on the planet, based on the data?

Perhaps I am biting off more than I can chew with my intentions here, so any advice would be appreciated.

If it helps, right now some of the areas I am most interested in rendering are: the view from the top of the cliff on the SE face of Olympus Mons, facing the eastern wall of Echus Chasma, parts of Kasei Valles, NW side of Hellas towards Hellespontes Montes, Pavonis Mons caldera, and, well... basically anywhere I feel like it once I get all of this figured out.

Anyway, sorry for the n00b questions. Any help anyone can offer (or at least nudges in the right direction) would be greatly appreciated. Thanks in advance. As a slight aside, I've done a bit of Googling, but a lot of things seem out of date. If anyone has any good places to go for Mars resources for Terragen (even just advice for setting the atmosphere correctly and such), I would love any links you can offer. Cheers.

[Henry Blewer]

It might be easier to use sections of the MOLA data. Say you wanted to render  Olympus Mons, You would really need only the data for that region. The region size would depend on how far away you started/ended with the camera.
I wish I could be more help. I have not tried this in Terragen 2. I did some using VistaPro 3 long ago; that was using DEM data, and limited by the maximum size of the landscape VistaPro 3 could handle.

[mamoru]

Thanks for the reply. I'd thought about this, but had had a few concerns about it. Am I correct in assuming that if I want to maintain proper horizons, I'm going to have to do something like this? http://en.tgblog.de/?p=40

One of my fascinations with Mars and something I'd like to try to accurately portray is the short horizons (about 3-4km) with huge features towering over them in the background.

Anyway, I was kind of hoping to avoid having to go through and cut out each section of the data that I would want to generate heightfields for (because even the smallest regions of MOLA data are 1/16 of the planet, so still huge enough to cause navigation difficulties), especially since TG2 can load the whole data set. Oh well, I'll keep experimenting and playing.

[Feenixnz]

to take things one step further....Lets say you want to render out a sequence where the camera starts out in orbit and you wanted it to then fly right into a specific location on a country. If I had say a DEM (or MOLA Data) for a planet (for an orbital view) and a DEM (or MOLA Data) of a specific location (for increased detail quality when camera is closer to the terrain), how would I set up a "transition between the two DEMs during the sequence??? Does anyone know if this can even be done with TG2   

[TheBlackHole]

Where exactly is the MOLA data?

[mamoru]

Where exactly is the MOLA data?

You can get the data sets here:

http://pds-geosciences.wustl.edu/missions/mgs/megdr.html

You have to download all the .img and .lbl files for a data set in order for TG2 to use it with the MOLA Map Shader. This means a bit over 500MB for the 64ppd data and almost 2GB for the 128ppd data. Otherwise, you can convert the images (which are RAW files with 16bits per pixel) to 16bit greyscale using something like imageJ and then use another program (I use photoshop and the SGI plugin) to convert to SGI so that TG2 can use it (since it doesn't like 16bit greyscale images in other formats).

To be honest, I haven't been playing much lately, so I haven't made any progress.

[cyphyr]

Its a long shot but take a look at Global Mapper. You can get a time limited key that will let you use the full features of GM including the export functions (.ter export is supported). Its a long time since I used it last but I'm pretty sure one of its features allows you to move map sections  to new co-ordinates (thus enabling you to move your area of interest to the datum).
Good luck and please let us know how you progress
Richard