Musings regarding scale - OR - LOD how good is it REEEEEEEALLY?

I just ran a quick thought experiment when I hit an interesting possible snag. I’ve been working on making ship models for a space game where the ships are in the hundreds of feet in length realm and I got to thinking about that compared to planetary scale.

I know that JMEPlanet uses LOD to help curb resource utilization at distance but is there an upper limit to when LOD just won’t be able to help with memory usage?

My thinking was this. If I have a ship that is say 100 meters long then the earth sphere would be approximately 127420 times that size across. Since the planet is rendered as a sphere (with varying surface detail albeit) would the model of the planet still be potentially too huge? I really should just attempt coding this before I ask to see what happens but most of these ideas come to me while I’m not at home.


You will have to make the scale relations entirely an illusion. As you found out yourself real relations just won’t budge. Check out the TestWorldOfInception class.

You cannot render space in trivial way on opengl hardware. You need to stay within a certain scale. If you want things measured in single meters visible up close, you cannot have objects further than 10km or so, regardless of how big they are. If you want to do that, you need to use tricks. Render to image and put impostors, render two scenes (far and close) and merge them together - but you cannot just throw universe onto GPU and expect it to render both mole on your avatar nose and Andromeda galaxy, all in same measurement units.

@normen @abies Gotcha. I really should take a serious crack at coding this stuff this week.

I was going to use your world of inception class for asteroid belts and planet rings (get closer to see the rocks etc). But I guess I’ll be leveraging it a bit more than I had thought. lol

@abies is there a term I should google or search in the forums for an example of rendering more than 1 scene and crushing them together?

Thanks all!

Viewports, render to texture
and pretty much every thread about space games.

@Empire Phoenix said: Viewports, render to texture imposter and pretty much every thread about space games.

You know… It’s kinda weird. And no offense is meant. But when I read one of your replies on this topic a while ago I actually thought you were just shooting down the guys post when you said Imposters. So ya. Today I Learned that that’s actually a thing in game programming. Thanks!