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Comment by m0zg | Hacker News Reader

> opaque workflow for beginners

Here's an example: say you want to punch some holes to mount components on a chassis. Say, furthermore, that you want to mount those components at an angle.

Here's what you do in Fusion:

1. Draw a sketch.

2. Rotate the component on the sketch about its center.

3. Subtractively extrude holes through the chassis.

In Fusion this is trivial and natural. Believe it or not, FreeCAD does not support #2. Want to mount several components at different angles? Fuck you, you need to draw each one of them pre-slanted already.

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FreeCAD 0.18 (releasead March 2019) supports such constraints. There are now many "Map Modes" for a sketch besides just "map to face" (the default, and in previous versions the only one). Unfortunately there is not really much intuitive UI available to start that workflow. You have to make the sketch with some/no mapping. And then in the Property editor for "Map Mode" click ... - from that point on there is a pretty nice dialog for chosing the modes etc.

In your case one can for example use use the NormalToEdge map mode, specify the degrees of Roll, and then use a Pocket operation on the sketch to make the holes at that angle.

There is also quite little documentation on these features, unfortunately. But here is an overview of some of the mapping modes. https://wiki.freecadweb.org/index.php?title=User:DeepSOIC

I don't know FreeCAD specifically, but #2 SHOULD be very hard. You do not want to rotate the part, you want to draw the sketch on an already slanted plane. Your sketch (and resulting solid) should be agnostic to reference plane orientation, otherwise the whole parametric model becomes "spaghetti code"

What? Maybe I don't understand the problem, but of course you can rotate elements in FreeCAD whichever way you want.

Select the object, set orientation in Placement / Axis / x,y,z

3D? Yes. 2D in a sketch? Nope. It's all parametric, everything has to be defined through constraints, and there's no way that I can see to define such a constraint.

Easiest way I've found is:

- Create a square via the CreateSquare[0] icon

- Put the lines as construction line

- Constrain the holes to the corners of the square.

- Add an angle constraint on one side of the square as you need.

It's easier than constraining your holes on a rectangle on which you have to replace the horizontal and vertical constrains afterwards. And you get to keep all those parametric variables that make changing something afterwards so easy.

[0] https://wiki.freecadweb.org/Sketcher_CreateSquare

To extrude a complex shape from 2D I usually first draw the 2D design elsewhere (Inkscape or Affinity Design) and import to FreeCAD as SVG. This works very well.

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