issues on creating centerlines

[dr who]

Hi,

I have two situations, where I don't know, how to add centerlines.
First one is a hole, which is partly closed (selected face is open):

FC_Centerline_face.png (14.19 KiB) Viewed 1058 times

Only face of the "open" part of the hole can be selected. Other face is smaller than line thickness of solid lines. That results in centerline with wrong offset.
I don't like to guess, what the offset is, so I'd like to create a centerline from the existing elements.
As the circle is the only element, that is selectable and contains the whole circle, Centerline (horizontal and vertical) of a circle would be a nice feature

Yeah, changing radio button from centerline creation dialog to checkbox, so that horizontal and vertical lines could be created in one job - would be a nice extension too

Second situation where I can't create centerlines is this:

FC_Centerline_2_lines.png (8.15 KiB) Viewed 1058 times

I selected two lines (yes, they are hidden lines) and choose "centerline between two lines".
FC pops the error "endpoints are equal ... check parameters".
I have no idea, which parameters I should check.
If the parameters from centerline creation dialog are referred, they are correct.
Selected lines are vertical and vertical centerline should be created.
I even tried aligned centerline, but that fails too.

[chrisb]

There was an issue with such selections, but when I tried to reproduce I had no problems, even with very small circles (radius 1mm, scale 0.5). So please try the current 0.19 with its numerous TechDraw improvements.

[dr who]

So please try the current 0.19 with its numerous TechDraw improvements

I wanted to do so, but current (22522) fails on closing sketcher (endless loop without ui response).
So I switched back to the elder version, which is 22492 - don't have any newer.

[chrisb]

So I switched back to the elder version, which is 22492 - don't have any newer.

I don't guess that TecDraw changed since then. Can you upload the file with step-by-step instruction how to reproduce?

[dr who]

When you open the file, you can't miss the partial open hole.
The open task is to create a vertical dimension to the top-border of the part.

With "view frames" enabled, the center cross of the circles is visible - but if you create a dimension between centercross and top-border the dimensions helper lines start outside of the part without relation to the element, it belongs to.
You can move the dimension to the other side of the part, so that the helper lines cross the whole part, but that looks ugly.

Therefore a centerline would be nice to use as base for dimension.

[chrisb]

You mean like that?

Snip macro screenshot-37c850.png (4.69 KiB) Viewed 886 times

It works here so it must be something in the settings, I will have a look at them.

[chrisb]

Perhaps it is one of the scales? Please note that some of the values are only presets for new drawings.

[chrisb]

I found the discussion about center mark scale: https://forum.freecadweb.org/viewtopic.php?f=35&t=36697, but that problem seems to be the other way round.

[dr who]

You mean like that?

Yes, that's the ugly variant, that I don't want.

With "view frames" enabled, you could create a dimension of existing vertices to get the size of the center offset ...
But if you enter that offset in center line creation dialog, it does not work, as techdraw uses different units than 3D-model. So after all, centerline offset is just a guess.