Feature request: Tangent tool accepting several lines and curves

[openfablab]

I recently tried to make arc tangent to two lines simultaneously. Tangent tool did not accept selection of two lines and arc.

But it can be useful to select 2 or 3 lines with circle or arc which I want to be tangent, for example while positioning curve in corner of projected geometry (e.g. I did it to make fillet on complex shape).

More general, selection of any number of curves and lines can lead in setting tangent constraint between every curve and every line in the selection.

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[chrisb]

May I ask for the whole use case? I guess that such constructs are not used very often, and even in the extract shown in your post it looks like you should model it differently.

[Karl1459]

First thought. In my workflow, I would find a multi selection tangent useful. Perhaps as little as line-curve-line or curve-line-curve. Priority low as we currently have "full" functionality, this feature would only save a few mouse clicks.

After a little thinking (i do that on rare occasion) I tried selecting the tangent tool first... then clicking on each connected segment, and low and behold sequential tangent feature is already enabled! (.18).

[jmaustpc]

After a little thinking (i do that on rare occasion) I tried selecting the tangent tool first... then clicking on each connected segment, and low and behold sequential tangent feature is already enabled! (.18).

tool persistence came into sketch only moderately recently, I think it was FreeCAD0.17 but maybe not.

I recently tried to make arc tangent to two lines simultaneously. Tangent tool did not accept selection of two lines and arc.

But it can be useful to select 2 or 3 lines with circle or arc which I want to be tangent, for example while positioning curve in corner of projected geometry (e.g. I did it to make fillet on complex shape).

More general, selection of any number of curves and lines can lead in setting tangent constraint between every curve and every line in the selection.

sounds logical at first glance but it does not makes sense mathematically. The tool would need some universal method to determine which line or part of a line should be tangent to which other line. May seem obvious in simple cases but would very quickly become impossible to work out as things get more complex. For example you are assuming that it would be a arc/circle that is tangent with a straight line, that is a mistaken assumption because mathematically two straight lines can be tangent, they just line up with each other.

Also you mostly should not be applying Tangent between a line and arc, you most commonly want to apply it to the point on the end of the arc and line, not the lines them selves. Doing so makes the points co-incident as well as tangent.

The shape you have shown in your sketch would commonly end up creating an invalid sketch for PartDesign WB. Because the lines should end where the curve begins, I understand that you have just shown an example but still for PartDesign WB it does not look like a good workflow.

The usually most efficient way to produce multiple connected lines and curves is to use the sketcher polyline tool using the "m" key to iterate through the different modes, see the wiki here Sketcher_CreatePolyline

[openfablab]

The shape you have shown in your sketch would commonly end up creating an invalid sketch for PartDesign WB. Because the lines should end where the curve begins, I understand that you have just shown an example but still for PartDesign WB it does not look like a good workflow.

In this case straight lines were taken from projected geometry. I just tried to make a fillet on the corner of complex shape. When corner have steps, holes, different curvature connections of other features, common PartDesign.Fillet tends to be confused with this stuff. But cutting a pocket usually gives a perfect result.

There are another reasonable cases for this. I often place holes on complex parts, and to be sure they are situated on proper distance from edges and each other, I draw auxiliary (blue) circles of corresponding offset diameter around them. These circles sometimes fill corners, like in my example and it is a good way to aesthetically put holes and other features when their bounding circles of the same diameter are tangent. Here multiple tangent constraints allow to keep overall harmony while moving one feature or another. This can be of course implemented by lines, but circles are more evident.