Parameterised rotating sketch

[DStuart]

Hi All, My first post here...

I'm not new to Pro_E, and would consider my self to be quite proficient, but this ones got me wondering!

Let me give some background to my question.

I am trying to build a parametric model (of a wing), and am having issues with controling sketches that are composed of both splines, straight lines and radius curves.

Basically I have geometry that cant be defined by a known airfoil (ie imported points), and must be sketched over an imported surface facet feature created using photogrammetry software. The surafce feature is only the top of the wing and the geometry relative to this surface is known to be a flat surface at a tangent to the leading edge radius...

I then make datum curves through this surface feature using xsections and use those curves to sketch splines that define the wing geometry at a given section.

I have no problem at all creating a swept blend between these wing section sketches to create a wing model that is a copy of the original wing geomerty. However I need to control the wing twist (washout) as a function of span. SO each section needs to be able to rotate about the centre of teh leading edge radius.


All that to get to my question which Im sure has a simple answer...

Is there a way to grab a sketch as a ridgid body and rotate it about a sketched coordinate sys whose angle of rotation is controlled by relation to a parameter theta defined as an angle to the global coordinate system...

I have had success with dimensioning just a spline curve to a sketched Csys, but as soon as I add any of the rest of the wing section geometry, the sketch either no longer rotates with a change to the parameter, OR the spline goes nuts to accomodate the change. I need that sketch to move as a ridgid body... just rotate!

Any ideas, suggestions etc welcome... Or a solution! Any more infor needed?

Thanks!

 

[spidernate]

You should be able to define your csys (outside of the sketch) with a defined angle to the global csys, and then define your sketch based on datum planes through that csys to determine your sketch plane and horizontal reference. What version of Pro/E are you using?

 

[rklatte]

Just so I understand, each sketch section is the exact same
except for being rotated & translated relative to the
original?

If so, try copying/pasting the sketch curve as a new curve,
then do a copy/paste special "move" on the new curve. I
think then you can use the length & angles in a pattern.

 

[jraquet]

An old blend, general form would work:


I made a simple section as a sketch, then started a Blend > General.


Use a sketched section and then "use Geometry" to import the sketch(es).


Rotate around x, y, and/or z axes.


Here I used Section 1, the made a second section with a z-rotation of 20 degrees and a length of 12.


View attachment 4666





Here I included a third section (2nd rotated 10, 3rd rotated 20).


View attachment 4667


You should be able to do the same thing (easier) with a swept blend by making a reference (datum axis) in the original and creating an angle offset for the subsequential sections. This would allow offset placement from the base rather than from the preceding sections.

 

[DStuart]

Hi,

Firstly thanks for the reply's, sorry I didnt get around to checking this as I managed to solve the problem the day after posting...

Basically, I had worked out that you can dimension a spline to a sketcher CSYS and then dimension the Y axis (for eg) of the CSYS to the vertical datum plane (angle). No problem... the problem arose when I started to add straight lines etc to that spline to creat the wing section proper. I ended up solving the problem out of the blue when pulling my hair out I said out loud "All I want that point to do is scribe a locus of constant radius around the axis of rotation!" and it hit me... I drew a construction circle that passed through that point with its centre at the origin of rotation and as long as all parts of the sketch are tangent problem solved!

I can post a picture of the sketch and model if anyone is interested to see it. I just dont have it on hand at the moment.

Oh and @rklatte, no not every section is the exact same, but all sections have a very similar shape. I first modeled the wing in its position as defined by the photogrammetry created surface. then those sections were individually copied to a new part, set up as described above and used to create a swept blend that obviouly changes shape when the angle that each section is rotated changes. This is controlled by a Datum graph which takes flight test data to reflect the real wing shape (its a flex wing). And its robust enough that I can make some rediculous graph shapes and the sections/blend holds together.

Thanks again


Edited by: DStuart