cartesian coordinates and round planets...

Started by romrom74, December 21, 2006, 08:07:49 am

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Hi it's my first post here as I'm just beginning to play with TG2. I was toying with the ability to create whole planets with procedurals and I wonder how it is possible to place accuratly heightfields, or lakes everywhere onto the global planet surface. When I use the translate handles, the feature I'm moving doesn't follow the curvature of the planet and I'm not able to edit the Y up coordinnates. I'm not even talking of geo-referencing here, I'm just curious if the capability to work with geo-centric or round coordinnates is planned to be added...that would be a must!


At the moment, all points on TG2 are referenced from a center point on the surface of the planet.  Based on that point, linear (not spherical) coordinates are formed.  This can be confusing, but think of the confusion that would result with three planets, each with their own coordinates and centerpoints!  So while this system can be a little confusing and irritating for dragging things around, all in all I think it's the best one right now. - A great Terragen resource with models, contests, galleries, and forums.



This means that no matter how many planets in a scene, the coordinates are always referenced from the first planet, correct?
So this is Disney World.  Can we live here?


Correct.  While you can change the location of the center point, there's really no point to it (pardon the pun ;)). - A great Terragen resource with models, contests, galleries, and forums.


I'm aware that this is inconvenient right now, and I think we are going to need latitude and longitude positioning for some (or most) objects. You will probably see this feature added first for heightfields, lakes and similar items.

Just because milk is white doesn't mean that clouds are made of milk.


I imagine it would be nice to be able to move objects by using other objects as coordinate references, or something like that. Have object positions be based on where they are with respect to another object. That way I can have different objects referenced to different planets. It'd be nice to have such and such objects at that planets lattitude and longitude (if that feature is added in the future) and this other collection of objects to be at the lattitude and longitude points of that other planet way over there.


I think the biggest thing that messes me up in the current system is having 0,0,0 on the surface of the main planet, rather than the center of the planet.  Moving the camera around in the 3D view while on the "other side" of the planet is tricky and at time frustrating.  ;)



Hey lets say you import a 406x4096 .ter terrain and map it to a planet thats really small (small sphere).  How would it blend its edges?  Would it also warp the terrain and wrap it around the sphere?
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Using heightfields on very small planets will usually cause problems since you can't adjust the projection/"mapping" method of the heightfield. For now you can use an Image Map shader instead and use Spherical projection. I'm not sure what image formats are available that support 16+bit grayscale, which would be needed for proper accuracy in the "heightfield". More info on using an Image Map to wrap around a planet can be found here:

- Oshyan