Create normal map from mesh with reduced-resolution mesh subtracted?
HI folks, I'm still pretty new at this, so maybe I don't say it all correctly. I made a grayscale hieght map from NASA topographic data and imported it into Carrara as a terrain. But the dataset is so huge it brought my computer to its knees.So instead, I first pulled up PhotosShop and made a normal map from the high-res satellite grayscale data.. Nvidia's PhotoShop plugin for making normal maps went into lala land, so I installed xnormal, which worked a little clumsily, but it worked.
Then I exported the terrain from Carrara as an .obj file and mported it back in as a vertex object. I opened the vertex mesh in the Carrara editor. I decimated it and untrangulated it very carefully, as each mouse click took at least 10 mminutes. Finally I got the mesh down to a reasonable size, so now I have a lo-res mesh from the same data, and it's really smooth:)
So then I imported the normal map I'd made in Photoshop from the high res data and put it on the low-res mesh as a bump map. Now the low-res mesh has high-res detail. BUT it''s overemphasized and jagged. What I need to do is 'subtract' the low-res terrain from the high-res terrain and make a normal map from 'height difference.' This must be something other folks do for other data, and itg should be easier with a terrain mesh, which at least has a flat bottom and exactly the same bottom corners.
Is ther a way to subtract one mesh from another and get the difference data in Carrrara?