3dsketch dimention between bends

[Anonymous]

Hi all,

Surprised I couldn't find any search results for this which makes me wonder if I'm missing the obvious...

I have a 3dsketch which consists of 3 lines, the 2 middle nodes then turned into bends.  What I'm wanting to do is ensure that the straight section between these 2 bends is as close to 0 as possible however when I dimension the straight section between the bends it references to the original bend nodes and doesn't simply dimension the section of straight between.  Is it possible to do this so I can lock the length?  The shape is quite organic but the bend radii are set figures so I can't use splines.  The goal is to be able to manipulate the path and bend positioning while the sketch locks the section between the bends to the figure I set.

I've attached an image for clarity.

kelly.young has embedded your image for clarity.  

Cheers,

[martin.jacko]

Hi Ospi,

It's difficult to imagine your situation. Could you please provide dataset and video?
There is simple utility for creating videos.
https://knowledge.autodesk.com/search-result/caas/simplecontent/content/download-autodesk-screencast...

Thanks,

Martin

[Hochenauer]

The way things are set up in 3d sketch, the remaining length of the segment in between is driven (a result of other inputs). It would be possible to use trigonometry to calculate the required length between the middle points (256.275), allthough that likely changes angles which again changes the resulting middle segment. Are the outer endpoints of your lines movable? If so, you could keep the angles intact and manually calculate where things need to go using the available driving dimensions for radius and distances.

Sorry for not having a better way off the top of my head. I'll keep thinking about it for a little while and report back if something comes to mind.

Have a nice weekend,

Gerald

[torbjorn]

I am still on Inventor 2017, and at least in this version this is not possible.

But with quite a few years of experience with this program (and its inconsistencies), my toolbox of workarounds are getting well filled.

In this case you can create your three lines, but instead of placing bends, you need to create an arc in each corner. Set them up to be equal and tangent to the lines, and trim off the corners. Now you have the actual line between the two 'bends'. 

Torbjørn

Inventor 2017.4

[Anonymous]

@torbjorn Thanks for that suggestion I tried it and it works well to set the middle segment but found it wasn't very versatile when I want to adjust the path arbitrarily.  I think I'll use this method once I have all the paths close to their final positions to set the middle segment lengths to a figure to make the fabricators life easier.  Cheers!

[Anonymous]

@Hochenauer Unfortunately the paths are very arbitrary and I am constantly adjusting them in all 3 dimensions in order to find the best routing for the exhaust system.  As you can imagine, trying to path 4 pipes out of a cylinder head to not touch, avoid crossmembers and oil lines while all having the same total length is quite a challenge!  

Not having control over the middle segment isn't a dealbreaker though, it was more something which would save me some time, I'll just have to manipulate the paths manually to minimise the gaps between bends as I go.

I have created quite a wish list with inventor 3dsketching as I have worked on this project though, certainly some things which would make things quicker but I'm guessing the demand doesn't really exist for this kind of path creation.