3d modeling from photographs

[SethTrey]

Hi all,

I'm trying to model a fixture used to test inertial measurement systems, (measuring MOI) and as such the fixture needs to be modeled with great precision. It is also extremely tedious because it is a random weldment, essentially designed to be cheap and heavy, not precise.

I was wondering if Pro/E had any system to model from a photo. That is, if there is any way to import a photo onto a plane, set up a coordinate system and perspective to match the photo, and copy that in 3d. If so, can it do any image analysis (edge finders, etc.) and can it use multiple photos?

If you need a rudimentary example of what I'm talking about, search "Google SketchUp Photo Match".

Thanks,
Seth Trey

 

[Aryanshome]

Have you tried Pro\ISDX? It is close to what you are looking for.

 

[Guest0527211403]

ISDX is indeed the closest thing (Look for "Trace Sketch" within the Style feature.

However, based on the problem description, it probably won't work.

Photographs are subject to the laws of perspective (parallel lines seem to converge to a point). Images projected onto planes in ISDX, however, are best when they are orthographic projections. Any distorion due to perspective will have a negative impact on the resultant model's precision.

You may be on to something with using Sketchup, as it uses the laws of perspective to its own advantage. You can maybe use sketchup to get the basic shape and look up one of the many ruby scripts that let you export it to STL (search for SU2STL). If you bring the STL into pro, you can model "on top" of it with regular features.

Another option is to take your photographs of your rig with a Telecentric lens (

http://www.opto-engineering.com/telecentric.php

). In that case, the ISDX module might work out well for you. Include a ruler or something of a known length in your photograph to scale it properly.

In any event, depending on how precise you actually need your model to be, photographs may not do the trick. It may be best to switch to a coordinate measuring machine (CMM), as that's a pretty guaranteed way to get accurate measurements.

 

[SethTrey]

Thanks for the information guys, it's really helpful.

I've learned the word I'm looking for is "photogrammetry." You're right about the perspective distortion, but photogrammetry operates with that to generate the 3d images.