Generate Point and Axis from 3D-Location and Unit Vectors

[howieryn]

Hi CREO geniuses,

I would like to constrain a part to an assembly as point-to-point and axis-to-axis (the other DOF/clocking is not important for the sake of this request). The point and axis are to be defined by a 3d parametric point file (.pts) which I've successfully been able to integrate using the "offset coordinate system" option of the point feature. I would like to create an axis or line from those points whose direction is defined by either unit vectors (x-y-z) or clocking angles.

Location Unit Vector
0.0249 0.525 0.0305 0 -1 0
0.0249 0.525 0.4515 0 -1 0
0.4571 0.525 0.4515 0 -1 0
0.4571 0.525 0.0305 0 -1 0

Does anyone know of a good way to do this? I have alot of these points (the above is just a sample), so looking for a nice clean way to handle it.

Thank you to everybody in advance! 🙂

[tbraxton]

If I am understanding the verbal description correctly this might satisfy your constraints and reduce the manual creation steps somewhat and lock down all 6 DOF.

Can you offset a coordinate system in lieu of your point and orient it using direction cosines (angles)? This would give you a csys at your desired origin with one axis (of your choosing) representing your desired unit vector direction. You could then assemble your parts using the csys to csys alignment constraint.

If this works then you have the option to create a UDF or use copy->paste_special using references to speed up creating multiple feature sets.

[howieryn]

Thanks for the quick reply! I have tried to dynamically offset a coordinate system from a reference coordinate system using the "offset coordinate system" feature, but I think it's restricted to points only. Do you know of a way to offset a coordinate system (CS) from a reference CS? It would be great if I could limit the input to one .pts file or something along those lines as we are still early in the design process and the 3d position and unit vectors will definitely change.

I can pretty easily generate angles from the unit vectors, but don't really have experience generating user defined functions into CREO--could probably look into it.

[tbraxton]

There are four options to offset a csys relative to a parent csys. Cartesian, Polar, Cylindrical, and from file. From file makes use of a text file defining a transform matrix. You can export it (transform file) from Creo directly assuming you can measure between two datum csys. You can then read that in when creating a csys in a model and reference the appropriate transform file.

To create a transform in Creo use Analysis->Measure->Transform. You can save this file from the measure UI to be used to create your new features.

Of course if you need to do this 100+ times then you may look into a script(s) to write the transform files for you to save time based on your existing coordinate and angle data.

[howieryn]

Thank you. I will try to generate the UDF and see what I come up with! I'm sure there's some resources online. I'll look into it and reply back to this thread.

[howieryn]

Also, if this is something you've done before, a list of instructions would be really helpful to save time in figuring out how to set everything up!

[tbraxton]

I would suggest the following approach if you do not have experience with UDFs:

1) Get this to work manually with the creation of one set of features that satisfy your design constraints.

2) Use copy paste special and use new references to duplicate what you created in step 1 in the same or another model

3) Analyze the parent child reference structure of what you created in step 1 with an eye toward minimizing the references needed to create the new features and referencing parents that will exist in new models and are likely to remain stable in the models you want to use them in. 

4) Create a UDF after completing step 3