Height Information on LWO Export Wrong

Started by oliverz3d, September 07, 2009, 03:47:42 PM

Previous topic - Next topic

oliverz3d

Tested out an export to Lightwave of the terrain I had acquired from the USGS seamless server. I used the Heightfield Export LWO operator, but it always comes into Lightwave with height information several times greater than it should be. So much so, that until it's scaled on the Y-Axis, the terrain isn't even recognizeable.

I'm assuming this is due to the terrain segment being quite a bit above sea level, so in Terragen the terrain sits on its own plateau. Yet in Lightwave, that plateau is being ignored, but the terrain's height includes the plateau's height, subsequently stretching out the terrain. Based on a height measurement in Terragen, the scale can be adjusted accordingly in Lightwave, but is there another way to have it imported with the height correctly (and continue to exclude the plateau/adjustment from sea level)?

Thanks.


cyphyr

Interesting. I've never exported a previously imported terrain and compared heights so I cant comment specifically.
However I have successfully exported terragens own internally generated procedural terrain as a Lightwave mesh, used that mesh as a basis for motion paths and models, and then re imported those back into Terragen. Everything worked and was in the right place. So I'm think there was no miss-match in the height data.

Two things come to mind, firstly the further away from Terragens own internal zero point (0,0,0) the more inaccurate it becomes. There are work arounds for this but I'd have thought that Planetside would have taken this into account when they made the importer. ALso the reverse may be true, the Terrain may only work properly when positioned correctly on the Planet.

Secondly I don't use the Heightfield Export LWO operator, I place a camera (set to ortho, size to the dimensions of my terrain) vertically above the center of my terrain and use the "Lwo micro exporter" located at the bottom of the render nodes far right tab. It gives greater flexibility of resolution, takes longer and created HUGE files :) (Oh and if you switch of the atmosphere and place the sun behind the camera gives you a great texture map :))

Sorry I couldn't be of more help, good luck

Richard
www.richardfraservfx.com
https://www.facebook.com/RichardFraserVFX/
/|\

Ryzen 9 5950X OC@4Ghz, 64Gb (TG4 benchmark 4:13)

Matt

#2
Ah, I think it's because the LWO Exporter hasn't been updated to use the georeferencing data. Only the Heightfield Shader knows what to do with the information. Other heightfield operators (including the LWO Exporter) still assume the heightfield has a regular grid spacing, and it's probably not even close to being the correct values for georeferenced heightfields.

One workaround would be to generate another heightfield from the displacement provided by the Heightfield Shader. The new heightfield won't have any georeferencing information - it would be at the position and resolution you choose. You'd be resampling the data, however, so you will lose some accuracy, and you'd have to carefully set up the position and size of the new heightfield.

Another solution is to use the LWO Micro Exporter method, which exports the micropolygons generated during a render. There are a few threads about the LWO Micro Exporter.
Just because milk is white doesn't mean that clouds are made of milk.