# Sweep along multiple curves - basic logic behind it

Hi,

I know this topic has been discussed many times. I read many of them but as a beginner in Grasshopper I don’t understand the logic behind it.

So what I’ve managed to do was: 1) “imported” the curves from rhino to grasshopper 2) with “Evaluate curve” function I’ve managed to get a point at one end of the curve + tangent at that point 3) I’ve created a plane on that point 4) and on that plane I’ve created a circle (SECTION)

So then I try to make the sweep by connecting the SECTION circles with the curves “imported” to grasshopper. What I get is a complete mess - the sweep geometry goes all around the place.

3_2.3dm (934.1 KB)
3_1.gh (10.3 KB)

Can you please point me in the right direction?

You need to graft the rail and the sections going into your sweep node.

Thank you Ryan! That worked!

So now I want use the sweep object as a cutting tool - I use “Solid Difference” for that. But not all the sweeps got cut, only a few of them. I can’t seem to find the reason why this is happening. Does somebody have an idea what’s going on?

Big thanks,
m

3_3.3dm (966.7 KB)
3_3.gh (11.0 KB)

I’ve solved the above mentioned problem by redoing the base geometry - obviously there was something wrong with the original geometry.

But I have another issue now. The “Solid difference” cuts the object with the sweep, BUT the top surface remains closed, even though the sweep object intersects it. But the “sweep canals” are visible beneath the surface.
Somebody has a clue?

Thank you,
matej

3_4.3dm (1.1 MB)
3_4.gh (12.1 KB)