SOLVESPACE -- parametric 2d/3d CAD

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Point on plane. Wrong wrorkplane? (by Robin M)
Hi everyone,

I am trying to model a mandrill assembly for a moving artwork. I actually intend on using a lawn mower mandill, here is a link to the actual part:

I have drawn one of the gussets but I am running into two problems. First, I cannot constraint the base of the gusset to the top face of the circle base of the mandrill. If i select a point on the base of the gusset, then the face of the base and press O, I get the red background of death.

The other problem is that if I try to step and rotate my part, it happens but on the workplane of the part not around a workplane parallel to the circle base.

This makes me assume that I should draw my gusset on a plane parallel to the circle base instead of perpendicular to it but it is not compatible with the way I wish to extrude it as the gusset is by nature perpendicular to the base.

Thank you for your time.
Sun Jan 19 2020, 09:40:55, download attachment mandrill.slvs
(no subject) (by Robin M)
OK so thanks to this thread ( I realized that what I seemed to be doing wrong is try and apply the constraint in an extrusion group rather than a sketch in plane group. So I created a datum in a new workplane group at a distance from the center equal to the radius of the cylinder it's flush with and constrained a base point of my gusset to that.

Now because the cylinder is rounded I need to bring this datum point a little bit inwards for the cylinder and the gusset to actually "merge". Is this good enough for a CNC mill or a 3D printer or is there a tchnique to somehow merge these two objects together properly?
Sun Jan 19 2020, 10:21:37
(no subject) (by Andrew)
To deal with the gusset/cylinder junction you do need the gusset to start inside the cylinder. You can achieve this by fixing the outside point on the base, and then setting the length of the gusset to bring it back inside the cylinder. Drawing it without intersecting the cylinder is the best way of creating the triangle, so that you can see what you are ding, and select its top point for setting the height.
Sun Jan 19 2020, 13:37:33
(no subject) (by Robin M)
Thanks Andrew.

So there is nothing wrong with having two positive extrusions overlapping? Would a CNC mill or a 3D printer controller software would treat them as one object ignoring the part of the edges that are shared between the two objects?
Mon Jan 20 2020, 09:14:45
(no subject) (by Andrew)
The union operation creates one object from the two, and so overlaps are ignored. Indeed an intentional overlap can be used to get rid of errors caused by problems in the NURBS library, see this threads;parent=2902&tt=1576519154.
Mon Jan 20 2020, 09:46:34
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