Datum plane tangent to surface

[FredOP]

How can I make a datum plane that would be tangent to the surface ? Or at the point on the surface closest to fixed point in space.

[chrisb]

It is not yet possible to place a tangent in Sketcher in the middle of a B-spline, leave alone a to curve controlled by such B-spline. You can compose the B-spline from several tangent segments though and use the endpoints.

[freedman]

Here is another option. Create a datum plane above the shape and scar the surface with a sketch. This gives you two lines ( in Green) to create an additional datum plane that is tangent, we are splitting hairs here but at least this gives alot of control on all surfaces.

[saso]

revolution_tangent_plane.FCStd

(14.51 KiB) Downloaded 31 times

DatumPlane is using edge of the Revolution as support and is set tangent to the surface by FrenetTB map mode and positioned by the map path parameter.

planebyedge.gif (805.37 KiB) Viewed 1478 times

DatumPlane001 is using the DatumPoint and the face of the Revolution as supports and is set tangent to the surface by the TangentPlane map mode. DatumPoint is using the Line and the face of the Revolution as supports, you can double click on the Line and move the outer point around to change the position (activate the DraftWB before). Instead of the Line you can use a sketch or other tools to have a more precise control over the exact position of the DatumPoint.

Note, regardless if you use the Line, the sketch or some other similar tool, you don't have to make the line tangential to the surface, the line is used only to drive the position of the point on the surface, the TangentPlane map mode will make the plane tangential.

planebyline.gif (750.39 KiB) Viewed 1480 times

[freedman]

I can't wait to try this.... Really, I need to load the Draft workbench first, what's that all about? Loading it does what!
Thanks for showing this.

[chrisb]

DatumPlane is using edge of the Sketch as support and is set tangent to the surface by FrenetTB map mode and positioned by the map path parameter.

Is it possible to make it tangent to two points of the solid?

[saso]

Is it possible to make it tangent to two points of the solid?

I am not sure I understand the idea, on a curved surface like this the plane will always be tangent to it just in a single point, if you want to define a plane differently then you normally need three points to define it or a point and a line,... ?

[saso]

Really, I need to load the Draft workbench first, what's that all about? Loading it does what!

You don't have to do it all the time, just the first time when you open FreeCAD. It is because the Line is from the DraftWB and at least on my system it has given me errors that it does not recognize the command when I double clicked on it to edit it after I restarted FreeCAD, so it is just so that the DraftWB tools get loaded. But as I said you can use a sketch or other tools instead.

[mario52]

hi

tray Macro_WorkFeatures macro



mario

[Vincent B]

This a way to do that. 2 splines perpendicular to a line.
Then use the Revolve's vertex to hook a datumplane.