I've been having a lot of trouble with the forum lately. Time outs that make my replies disappear.
buick455 wrote:Yeah for the life of me I just don't understand how exactly you did the slots
My mini-tutorial shouldn't be seen as all-inclusive, I left a lot of details out. This is where a video tutorial would be better. I may try to make a few in the future, problem is the sound card's microphone jack in my new PC sucks big time. I'll need to buy either a new card or an USB powered microphone.
You should watch John Durston's videos on Youtube. They're more than 10-12 month old now, which in FreeCAD time makes them almost obsolete. But the one that introduces sketching and the other about degrees of freedom should still be relevant. https://www.youtube.com/user/5needinput
The problem you're having with the slot is probably caused by the tangent auto constraint that kicks in too soon. The dev responsible for the sketcher is aware of it. (Here's the bug report
A workaround would be to disable auto constraining (there's a tick box in the Task panel when in sketch edit mode) but you'd have to add a lot more constraints manually.
What I prefer to do is, when I have similar problems, to draw my geometry a good way out of where I actually want it, so the sketcher solver does not attempt to add constraints that I don't want. So click on the polyline tool, and draw your rectangle a good distance from the red and green axes. Also, create the reference geometry (the magenta arc) after
you've drawn the rectangle. That makes one less object the solver will attempt to constrain to.
When you've drawn the first slanted line, toggle the M key. This is the "modifier" key. The polyline has multiple modes. One of them locks the next segment perpendicular to the previous one. Then there are arc modes (perpendicular or tangent). Play with it, it's very cool, this is new in v0.13.
When you move your mouse pointer while drawing, watch the pointer icon. To the lower right of the cross an icon of the active tool is shown. When hovering over an element, a constraint icon will show up besides it to indicate that the solver detects a possible constraint. It is a smaller version of the constraint icons in the toolbar. When you click while a constraint icon is showing besides the pointer, the corresponding constraint will be applied.
Once you close your rectangle, you add the external edge constraint to the hole. Then, drag your rectangle to its approximate place. You select either a line or a point, then when it's green you drag it. When dragging a point you can rotate the rectangle. When you've dragged the sides near the circle, add the tangent constraints. BTW, you wondered about the fact you got a 3/4 arc. One of the lines may not be in apparent contact with the arc. This does not matter: if you apply a tangent constraint, the line will be positioned where it would touch if the arc was longer.
After that you set the length of the rectangle, then you draw the small line as I explained in my tutorial post.