Anyone know how to lock a spline length?

[David_M]

I can get as far as edit > convert to perimeter, but there doesn't seem much point in this as I can't lock the dimension nor can I link it to another dimension. Anyone know how to do this? It's for a spinal bend so as not to stretch the part when it's bent.

Thanks

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[Patriot_1776]

Not to my knowledge. But, not quite what you want, but you can make the spline longer, then put a point at the length distance you want, then copy the spline, then use the point to trim the curve to the correct length.

Yep, there's times when it'd be real nice, for cabling or routing etc. to be able to specify a length, and then end points, but I don't believe we're there yet.

[BrianMartin]

Wait a second David... it sounds to me you're on the right track. Make your spline, convert it to a perimeter dimension, and drive that dimension with the length of your solid object. I do this kind of thing all the time to minimize stretch on a spinal bend. Frank's idea of using a point along the spline as a trim point is also pretty novel. I hadn't thought of that.

Where's the problem though? If the length of your solid model changes, you want to spline to change too, right? I must be missing something because it seems like this is the right way to approach it.

[David_M]

Hi Brian

Yeah that's what I thought; and I do it all like that and it works until you try to move one of the spline points. Then eveything seems to get forgotten.

[BrianMartin]

Well you're a little stuck because you can only really use ONE dimension as a variant when you're creating your perimeter dimension. I am able to move around the spline points but I cannot add or remove them. Hmm... can you shoot a screen shot of the curve you're using? That would help us reproduce the issue.

Thanks!

-Brian

[Patriot_1776]

Kinda hard to suggest when there's no pics of what you want.

Does this help? I did this a couple years ago for someone here.

[David_M]

Well I don't have the actual one to hand, but the idea is to bend a flexible PCB through a slalom of gaps and guides in order to check the fit with the part geometry. I have the PCB imported from IDF and would like to be able to tweak my spinal bend without invalidating the feature (by changing the length of the part).

I have actually managed to sort it by drawing the spline more-or-less spot on, and then just editing the one point which Pro/E allows, but I think this is still an interesting modelling topic.

My sketch looks something like this:

[Patriot_1776]

So, you mean in sketcher itself? Looks like you got it. Still not sure exactly what you want.