Hi guys i would love to know how you guys would go about making this sort of closed spiral when already given a drawing of the spiral and some selected heights like shown in the picture but no 3d curve of the spiral

# How would you guys do this

**mitviz**#3

so sorry, here is a picture with measurements at the points i need it, the spiral needs to blend into the main part like in the picture also

**davidcockey**(David Cockey) #4

One approach:

Create a 2D version of the spiral

Extrude the 2D spiral into a spiral surface.

Create points on the extruded surface at the locations corresponding to locations where the height is given.

Use InterpCrvOnSrf to create a curve through the points on the spiral surface.

Trim the spiral surface with the curve.

Create a vertical line at the center of the spiral and put points on it corresponding to the heights.

Draw horizontal lines between the corresponding points on the surface and the points on the line.

Create the “ramp” surface using Sweep2 with the edge of the spiral surface as one rail, the vertical line as the other rail, and the horizontal lines as the cross-section curves.

Trim the rail as appropriate.

**mitviz**#5

That was perfect! I now have an almost impossible naked edge i cant seem to fix, i will upload the model i made, thanks a million David!

**lopacki**#7

Mitviz,

Not sure if this is what you were after. I attached your file I worked on a bit. I just used sweep 2 rails and worked my way up the spiral.

All my best … Danny

spiral model.3dm (391.3 KB)

**rramot**#8

Another way i found that work for me was to create a flat spiral and then use cage edit command to adjust the height and finish the model with sweep2