Author Topic: How to render high-res heightmap by using the Luminosity shader with a gradient?  (Read 147 times)

Offline rafaelz

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How do you use the "Get Altitude" node and take it into a luminosity shader and render it into a heightmap with a top-down camera?

I'm asking about the node workflow itself. I'm new to TG4 and don't really know how the nodes work together. I would really appreciate someone explaining to me which node goes with which and in what order.

I've read in the forum about someone using Linear Step so they can get a gradient using terrain altitude and then render with a top-down camera, but couldn't replicate that on my own: https://planetside.co.uk/forums/index.php/topic,23017.msg232972.html#msg232972

Why I want to use the renderer? Because I've tried the "Heightfield Generate" node, and I think the quality of the save file is not as good as rendering a "luminosity Shader" with a top-down camera render where I can adjust "Micropoly detail".

Ultimately, I want the best resolution heightmap possible from TG4 so I can save it as an EXR or TIFF and use it in other render engines like Octane with Cinema 4D.

I don't really need a Vector Displacement for overhanging, just a scalar displacement will be fine. And no need for a tiled map for now.. just the best quality single 8k heightmap TG4 renderer can provide, if that's doable.

Thanks for reading

Offline Dune

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You can also use a surface shader where you set luminosity with a gradient by altitude (max altitude white and an appropriate fuzzy zone. Then kill all lights (sun and enviro) and ortho render your terrain, save as 16-bit tif. No need for a compute terrain either.

Welcome, btw.

Offline WASasquatch

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It's cool to note that a Heightfield Shader can already present the shader in height with a solid colour (like white) to use as a Luminosity input on a surface layer or what not.

Example project attached.
« Last Edit: September 28, 2018, 05:45:42 PM by WASasquatch »
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Offline rafaelz

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It's cool to note that a Heightfield Shader can already present the shader in height with a solid colour (like white) to use as a Luminosity input on a surface layer or what not.

Example project attached.

Thanks for the file. It helps a lot to understand what you mean.

But I still get a blurry image on the render. Does increasing the Image width and height in the render node the only way to get better details? (If I were to add rocks and such on the map for example)

Offline Oshyan

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Your output really looks like low Micropoly Detail (MPD). Are you saving output of a preview or is this a final render? If it's a render, what was your MPD set to? Were you using Path Tracing?

In general the heightfield generator should give you good output, especially when saved to EXR. There are some details that are not possible or not easily represented in heightfields. The rasterization process itself may lose some detail. So you may be right that a top-down render will get you better results, but I am not confident in it. Worth testing I suppose.

- Oshyan

Offline Dune

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If you disable all lights and use the luminosity render time will be minimum, so you can easily do a 5000x5000 or bigger render at minimum 0.6 detail for best detail. Only takes minutes. If you have the pro version of course.

 

anything