Extruding dwire happen along the plane, not the normal

[Gunnar]

Hello,

Version 0.17, Git 13522

I am completely new to FreeCAD and I am struggling to do some really basic stuff, which actually says a lot more about me than FC . I am trying to make a architectural drawing of our house. I have a dwire as the triangle below the gable which I an trying to extrude along the normal to create a solid to use as the upper gable wall. But when I use the extrude tool, the extrusion is along the Z-axis along the plane and not along the Y-axis as expected.

Before extrusion:

before-extrude.PNG (24.76 KiB) Viewed 2081 times

After extrusion (3000mm just to show the issue):

after-extrude.PNG (32.92 KiB) Viewed 2081 times

Using the Y-axis as a custom direction work. I don't understand why using the normal does not work?

[chrisb]

Can you upload your file?

[DeepSOIC]

Hi!
Thanks for reporting. I actually expected it could happen when coding Extrude's normal direction determination.
DWire is Part2DObject, just like a sketch. Extrude assumes that Z direction of local coordinate system of sketch is always the normal. It gives much more predictable normal vector direction (whereas determining normal from shape itself may give it either up or down). And it treats DWire just like a sketch.

DWire, if drawn on any plane other than XY, violates that rule of Part2DObject. Unexpected extrusion direction is the outcome. I think, Draft should be fixed, but it can't be fixed completely (DWire can be a 3d curve, i.e. not planar).

As a workaround, you can make Part Compound out of the DWire, and extrude the compound. It should then fall back to determining normal direction from shape itself, and give a proper normal. Or just use custom direction.


Feel free to report it on tracker.

[meme2704]

there is a lot of note to make in your drawing
First, since you are new, I advise you to place the axes of coodornées, so you will see better in what way to go
If you want to do extrusion, you have to do only one Dwire closed at a time, no cross line
the extrusion is always in a direction perpendicular to the construction plane of the Dwire, it is set to 1 this direction, otherwise by default Z will be used
"following the normal" is used in case the Dwire is not in one of the 3 general plans
for the extrusion of curved surfaces, I give you an appointment in a few months, when you will not be a beginner, but "confirmed"
and I confirm Chris's request, attach your Fc file

[Gunnar]

Hi, thank you for the replies! Sorry for my late reply.

I continued to work on the drawing a bit, but I have attached a later version of the file where one of the Dwire gables are still there named Dwire005 (though I must have made it Window008 by mistake, but it still shows the issue). I did notice that the normal for the Dwires was set to [0, 0, 0] in one of the panels.

Thanks for the tip about showing the axis though I don't know how to enable it. In my case the model in not rotated, so it is fairly obvious in the current state.

I will try to make some kind of minimal example and submit a report.

[UR_]

Model stripped down

stripped.FCStd

(5.73 KiB) Downloaded 43 times

Code: Select all

obj = App.getDocument("stripped").getObject("DWire005")
obj.Shape.normalAt(0,0)

gives:

Code: Select all

Vector (1.0, 0.0, -0.0)

FreeCAD 0.18-000011.png (7.06 KiB) Viewed 1997 times

setting Extrude dir mode to "Normal" switches Dir to [0.00, 0.00, 1.00]

FreeCAD 0.18-000012.png (4.26 KiB) Viewed 1997 times

[Gunnar]

Nice, UR_.

I guess this basically what is needed for an issue report? Perhaps you would like to submit it?

[bitacovir]

As a workaround, you can make Part Compound out of the DWire, and extrude the compound. It should then fall back to determining normal direction from shape itself, and give a proper normal. Or just use custom direction.

Here there is another way.
* Draft Trim/Extend tool on the Dwire face