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TRUSS design, boolean issue
michael_stalls
Member Posts: 59 PRO
Hi all,
here are some images of a truss for the fuselage of an aerobatic aircraft i have been working on.
Making this truss has been somewhat tedious but i got there in the end. i made it by creating a box that represents the four outer longerons and the sketching side profiles on the faces of the box. i then swept the tube profiles along these side profiles. i made them mostly as seperate sweeps and then joined the using boolean union. When i tried to add yellow and blue tubes to the rest of the truss it comes back with an error "cant produce a valid part'' why would this be?
here are some images of a truss for the fuselage of an aerobatic aircraft i have been working on.
Making this truss has been somewhat tedious but i got there in the end. i made it by creating a box that represents the four outer longerons and the sketching side profiles on the faces of the box. i then swept the tube profiles along these side profiles. i made them mostly as seperate sweeps and then joined the using boolean union. When i tried to add yellow and blue tubes to the rest of the truss it comes back with an error "cant produce a valid part'' why would this be?
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brucebartlett
Member, OS Professional, Mentor, User Group Leader Posts: 2,137 PRO
I'd love more robust tools for producing part's like this. I can see those junctions are going to become quite complex and that would be my guess as to why its not working, a small bit on an edge somewhere. I'd be trying to trim bits back to simplify the whole model and find the problem area's 1 by 1.
What the end goal? This can make a difference as to how far to persist with problems like this.
Manufacturing drawings?
Models For FEA?
CAD data for CAM?
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bobt
Onshape Employees Posts: 7 
The most common cause of Boolean errors of this sort is trying to join tubes of identical diameter. A slight tolerance error in position, and now there is no longer a valid intersection. If possible I would make the cross struts slightly smaller than the lateral struts.
I can't tell from your images, but hollow tubes also make things more error prone, doing all the booleans on solid rods and then shelling the result, or worse case boring out the center, may also help.6
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What the end goal? This can make a difference as to how far to persist with problems like this.
Manufacturing drawings?
Models For FEA?
CAD data for CAM?
Twitter: @onshapetricks & @babart1977
I can't tell from your images, but hollow tubes also make things more error prone, doing all the booleans on solid rods and then shelling the result, or worse case boring out the center, may also help.
All the tubes are hollow and when i use translucent the intersections are pretty complicated...i figured it might be something to with this. Ill try making them solid next time i make a truss