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General => Terragen Discussion => Topic started by: doug.gann on July 24, 2022, 12:26:54 PM

Title: DEM edge problem
Post by: doug.gann on July 24, 2022, 12:26:54 PM
Hello, new to Terragen and trying to work with real world data in the Southwestern US.

I've run into an issue that does not seem to be covered in the tutorials, and I'm hoping someone can point me to a reference on how to fix the following issue:

I've downloaded a pair of adjacent 1 meter DEM geotiffs from the National Map, and while they import, and I can georeference the models to the planet surface, the edges of the DEMs are being pulled down to an elevation of zero, effectively ruining the accuracy of the models in these areas.  See attached image.  As my home is located in the area in question, I can assure you there is not a 600 meter canyon along the -111 degree longitude line. :) I tried to fix this by using the Load Multiple DEMs in the heightfield importer, but this option does not appear to be functional.

Any assistance would be greatly appreciated.   
Title: Re: DEM edge problem
Post by: aknight0 on July 24, 2022, 09:51:43 PM
Try setting border blending on the heightfield shader to 0, and try with and without stitchable border checked to see which looks better.  This will give a hard outer edge, but you can mask the entire thing with a simple shape shader if that's a problem.  Sometimes the edges of DEM's don't line up perfectly, and you'll get strange artifacts, but sometimes they do work.
Title: Re: DEM edge problem
Post by: doug.gann on July 25, 2022, 10:38:23 AM
Thanks aknight0.

Setting border blending to 0 renders the seam invisible.

-Doug