Creating Datum Curve from edge of complex curved surface 3

[treddie]

Hello.
Is it possible to create a datum from the edge of a complex curved surface, in WF4? Seems so simple, it may be one of those things that I answer myself as soon as I post this post!

Thank you,
treddie

 

[hydromech]

I do it by putting at least 2 datum point on the curve/edge.

I then put the datum plane or axis through these points. Datum planes can also be aligned to another plane or surface.

The position of the datum point can also be edited to adjust the position of the datusm plane.

It works for me anyway..?

Adrian

 

[jeff4136]

> Is it possible to create a datum from
> the edge of a complex curved surface

Assuming the desired datum is(?) a plane and the edge is nonplanar; you can create a plane thru point (on edge) and normal to curve (edge). You can also create axes thru pt and either normal to surface or tangent to edge. From there you can probably create most variations that might be desired.

 

[treddie]

Thanks for responding jeff, hydromech.
But all of those methods require the datum to lie in a plane, correct? In other words, there appears to be no way to, for instance, create a datum curve from the edge of a helix.
treddie

 

[jeff4136]

> "lie in a plane"

Not generally but I'm not sure I understand the goal.

Is a 'datum' a curve, plane, point, axis, gtol, ...?

> "... create a datum curve from the edge of a helix."

I assume create a copy of a helical surface / solid face edge?
To do that; select the edge (chain if necessary), CTRL+C, CTRL+V (copy / paste).

 

[mburlone]

If you would like to create a datum curve based on the edge of a helix, perhaps you can make the datum curve from an equation. Create a coordinate system at the base of the helix with the z-direction oriented along the axis of the helix. Go to insert > model datum > curve and select "from equation". Choose the coordinate system you just created as the reference and pick the cylindrical coordinates option.
You can then set the parameters for the curve. Let

r = your desired radius
theta = t*n*360 (where n is number of winds in the helix)
z = l*t (where l is the length of the helix)

This will parametrically plot the 3-D curve from t=0 to t=1

Good luck,

-Michael Burlone

 

[treddie]

mburlone >
Unfortunately, this is a freeform surface, with no equation.

jeff >
But you can't select an edge from a surface just by clicking on the surface's edge; all you get is the selection of the surface.

Please see attached. The idea is to copy one of the edges of any of the shapes as a separate Datum Curve. Although I've found the solution to my REAL problem in this instance, for other cases I've had, it would have been nice just to grab the required edge.

 

[jeff4136]

> you can't select an edge from a surface
> just by clicking on the surface's edge;
> all you get is the selection of the surface.

Correct, assuming 'Smart' selection filtering.
The next step (once the surface is selected) will select an edge. Assuming Pre-Select Highlighting On, passing the mouse cursor over edges will cause them to flash a different color (red to cyan on my system). Clicking on one of them will Select it (a segment) turning it bright red. Once a segment is selected you can Shift- Select a chain. Once the desired entity or chain is selected; Copy and Paste to create the curve feature.

Alternatively, set your Selection Filter to Geometry and you can go straight to the edge entity.

Watch the screen tips and the 'object focus' (I suppose it has a real name) indicator on the lower left extremity of the Pro/E window.

Variations in selection modes and filtering may require altering technique or be inappropriate. I think I saw a 'white paper' or tutorial on PTC's site addressing Wildfire entity selection techniques. Might be worth looking for.

> see attached

Bet I know what that is. ;^)

 

[treddie]

Ah HAAAAA! Pre-selection Highlighting was off by default. Thanks for the tip there. It just seemed dumb that ProE couldn't do such a simple task, which it turns out, it can.
Thanks everyone!
treddie

 

[treddie]

Actually, it wasn't that prehighlighting was off, it's that I didn't understand that you have to FIRST select the surface/solid, THEN move the mouse over the desired edge, per your procedure. I was trying to select the edge by right-clicking over a general area with nothing selected.