Awesome, Thanks for describing these features. I was actually just gonna try figuring these out today, and whatdya know, I get the explanation first. So, after pascals explanation I get it. For my notes, I gonna do a little screenshot example tutorial with arrows, letters the whole 9 and I’ll post it maybe. These roadlike functions appear to have no effect on a sweep of a rail that is completely flat to the cplane. In order to notice the effects, the curve has have a rise or dip in the z plane. So, for a quick description of how to notice it a little easier. Use rendered shading to help the curves show up a little better. Then using roadlike top preview, switch between freeform and roadlike top. You’ll note there is 3 lines you will see. 1 is the middle(if your crossection is aligned that way. The other 2 are the outermost parts of your crossections. In the Roadlike Top, only in the Top viewport you will notice that the spacing of the outermost portions of your crossection(horizontal portions of your crossection) is a constant. Here’s an example with numbers to it. If your crossections horizontal limits were 3mm, your crossection is 3mm wide. Now, divide that 3mm by 2=1.5mm These 3 lines you can see(outermost left of crossection, rail, outermost right of crossection)will be equidistant. from the rail, every point of the left side of crossection will =1.5mm, and hence from the rail to the right of the crossection will equal 1.5mm. Now this example only works like that if your crossection were centered onto the curve. This works the exact same for Roadlike Left, Roadlike Right. In all other viewports, these 3 lines and their distance will be variable. Also remember, the curve has to have z coordinates or have rise, dip in order to even show up. ALso note, that there is no roadlike bottom option, that is because it would give exact same results as the roadlike top. Thanks for bringing it up, I’m real excited to continue learning to be the best I can be in Rhino, and there’s a lot to learn. I’m do some screenshots/descriptions.
I am currently revising this post. I believe I do have it all wrong. They look like roads on top, roads on left, and roads on right, but they are variable.