Maxon Cinema 4D Forum
How can I extrude a loft?
How can I extrude a loft?
by Mahmoud Doe on Oct 11, 2019 at 12:14:46 pm

Hey guy, so i'm working on this project and I have a spline under a symmetry
and both under a loft!
How can I extrude the loft?

I tried to convert it to a polygon object and extrude it, but it didn't turn up very well!

Re: How can I extrude a loft?
by Steve Bentley on Oct 11, 2019 at 11:04:24 pm

It really depends on what the loft shape looks like and what you are trying to achieve. The idea with an extrude is that it takes the boundary shape and makes those the "walls" of a new taller object. With a loft, often there are lots of polys on the "top" surface.
What you could do though is select all the perimeter edges and then choose "edges to splines" and then extrude that spline. You will probably have to triangulate after that so you don't get bent polys (assuming the resulting spline is no co-planar).

Re: How can I extrude a loft?
by Brian Jones on Oct 11, 2019 at 11:07:07 pm

I’d have to see a picture of what you want to do I’m lost at this point.

Re: How can I extrude a loft?
by Steve Bentley on Oct 11, 2019 at 11:48:06 pm

Here's a project of the steps I mentioned. Don't forget to change the caps on the extrude to triangles or you will have bad geometry.

Re: How can I extrude a loft?
by Mahmoud Doe on Oct 12, 2019 at 2:22:37 pm

I appreciate your help guys, but i still couldn't do it.
here's the shape that im working on

Re: How can I extrude a loft?
by Steve Bentley on Oct 12, 2019 at 5:42:27 pm

On closer inspection of your set up - you already have the spline to extrude from. Get rid of that loft object.
Close the spline (the one side of the shape) with the check box in the spline attributes, then put that closed spline under an extrude, make sure to check "Create single object" in the caps tab of the extrude object. Make sure the extrude direction/distance is in the Y only. Then put all of that under the symmetry object and make sure to check "weld points" in the symmetry object tab.

The other thing you can do with that kind of shape is tuck it under a cloth object. Then you can set the thickness. It often creates geometry that can be problematic but it is a sort of extrude.

The reason your solution doesn't work is that the spline has a direction to it. When you use symmetry, the mirrored spline has the reverse direction so the two splines can't be joined by the system in one long continuous spline for extruding. Try it - use the spline on the one side and put it in a symmetry object, and then close that original spline with the check box. The end of the original spline will join to the start of itself and so will its mirror spline. So you actually still have two shapes in there. Unfortunately once you make the symmetry object editable you can't disconnect those splines, reverse one and then join them (which is what you would normally do when closing one spline with another). To join two splines they must be going the same direction. The tail of one joins up to the start of the other (you can tell the direction because they start out white and then fade to blue at the tail.)