# Can you have 2 spline profiles on one spline?

Im trying to make a road using a spline (I will call it road spline). I made a spline profile and attached it to original road spline and it gave me a nice walkway next to the road and it looks something like this.

Now I want to make the same walkway profile but I want it to be a little bit lower than the last one, it looks like this.

I made this using 2 profile splines and 2 road splines. Is it possible to make it with 1 road splines and 2 profile splines with nice blend with it.

This works in 3ds max, here is example screenshot from max:

Link to that max video: https://youtu.be/PdsnVQOlO34

I've never seen anything like that with curve profiles so I don't think you can do it in blender. If you are fine with a different type of modeling here's what you could do:

Instead of making the main road using a curve as a profile, use that profile to make a solid segment of the road that can be turned into an array. Then make the array fit the length of the curve you want to use as the curvature of the road

You then need to make a segment with the detail that you want, like the ramp. You can duplicate the arrayed object (main road) and apply the array, then use that as the base of the ramp so that the edges match with the arrayed object. Once you have the ramp modeled, you can create a cube around it that is slightly narrower and use an Intersect boolean modifier on it:

This same cube is used in a difference Boolean with the main road:

This results in a segment of the main road being removed and the ramp segment taking it's place. (Parent the ramp to the cube and the cube to the main road so that everything stays in place if you move it. This lets you hide the ramp so it's not in the way).

If you want the geometry to merge into a single piece you can create a simple geometry node set up on the main road that joins its geometry to the ramp's and then merges the vertices by distance. The result of this is that you can move the cube along the axis of the array and it will change the position of the ramp in the array. You can then give the main road a Curve modifier and make it follow the curve that you were using for it:

It's not as simple as the 3dmax thing but the advantage here is that you are not just working with curve profiles so you can add a lot more detail than with an extrusion. I'm pretty sure someone who knows more about geometry nodes could reduce all of this to a single setup instead of multiple modifiers on the main road but I'm not there myself. As for the lofting part, you can do that with the Bridge tool on the Bool Tools addon (Comes with blender)

• Thank you, I will definetly give this a go. Commented Jul 20, 2023 at 7:19