This is cool. It’d be interesting to compare the authoring UI & workflow & relative merits of curve-authored terrain to surfel-authored terrain. And those shoul

This is cool. It’d be interesting to compare the authoring UI & workflow & relative merits of curve-authored terrain to surfel-authored terrain. And those should be compared to patch & poly workflows, as well as painting tools like Zbrush. I can imagine authoring unstructured curves to model a surface can be quite nice for certain things, but you probably do lose some advantages in other methods. > I cannot stress this enough the thing we want here is the thing you're probably used to calling "the surface normal", but—for reasons I am not responsible for—the thing we want is instead called the "binormal" here and the thing that is called the "normal" is instead a different thing. Why did the mathematicians do this to us?! In case the author is reading, this paragraph has a some misconceptions in it. Mathematicians did not cause your curve binormal to line up with your surface normal, that’s something you have control over. Curve normals will not usually be tangent to your surface, and binormals will not usually line up with a surface normal. There are multiple valid ways to define a curve normal & binormal. The most famous curve normal is the “Frenet” normal, which is by definition pointing in the direction of curvature. If you use the Frenet frame, then the curve normal will be close to (but not exactly the same as) what you want for reconstructed surface normal. You can for sure set up your authoring system so that a curve normal you define is the surface normal you want, and the curve binormal becomes one of the surface tangents. (Curve tangent will be the other surface tangent.) One thing that might be really useful to recognize is that even when curves have an intrinsic normal and binormal provided by your curve authoring tools, you can assign your own normal and binormal to the curve, and encode them as offsets from the intrinsic frame. (The “Frame” is the triple of [tangent,normal,binormal].) If Blender is letting you control the curve normals without moving control points, then it’s already doing this for you, it already has two different frames, and internal one you don’t see and a visible one you can manipulate.