SW2011 Sweeps following path

[drawoh]

I am trying to model an optical system with a bunch of mirrors. The best way I have found to do this is to model the aperture, and then sweep along a set of centreline elements. It is a fairly simple matter of geometry to reflect these centres off of flat mirrors. This worked fine on SW2007.

SW2011 does not seem to want to follow oblique angles. The resulting body is "topologically invalid". SW is perfectly happy if I change the sweep to "keep normal constant", but this is not a particularly accurate represntation of the optical path.

Has anyone experience with this?

I have attached my sweep sketch to this. The oblique angle is around 17[°].

Thank you.

JHG

 

[rbpmc]

Is there any particular reason you have to do this with a single sweep?

 

[CorBlimeyLimey]

Can you post the actual path & profile?

I just did a simple look-alike test (with SW2011) without a problem.

 

[EEnd]

Attached is a sample of the technique that I used. Basically I unfold the optical axis to a straight line, use a loft from aperture shapes at both ends to get an unfolded solid and then mirror and cut (without merging bodies) to refold the solid body. There are a lot of steps but it provides the bounds of the ray bundle along the entire optical path.

Eric

 

[EEnd]

Here is a screen shot.

 

[drawoh]

Here is a similar model that also screws up. I have an oblque angle set to 35[°]. When I change this to 30[°], I get the error message.

JHG

 

[drawoh]

EEnd,

Thank you for the model. I have done it that way in the past, and it has the advantage of accounting for the field of view of the lens and light bucket/image plane. I got into the sweeps in SW2007 because it was a lot less work, especially when you tidy up behind the mirrors.

I may have to go back to this.

JHG

 

[Eltron]

If you're not doing a loft like eend's model have you thought about using weldments?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[drawoh]

Eltron,

It is not Eend's lofting that works. It is the mirroring, especially when you remember to not merge everything.[ ]

Welding must might work. It lets me take advantage of my 3D[ ]routing sketch.

JHG

 

[CorBlimeyLimey]

I usually create the mirror or grating surfaces, trim them back to the illuminated shape, and then loft between the resulting surfaces.

 

[CorBlimeyLimey]

Here's an old thread with another method by APPENG
thread559-206224