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MeDaveo1-Visitor
1-Visitor
December 8, 2011
Question

Problems creating a coiled bulb filament.

  • December 8, 2011
  • 1 reply
  • 5757 views

Hi There,

I'm a little new to Pro-E so please bear with me on this. Thanks.

I'm currently using WF4 on 32-bit XP and need to create a bulb filament i.e. a helical coil. I've looked at some other examples of this requirement but am still a little confused as to the process right from the beginning.

I have created springs using a helical sweep as this is fairly straight forward but my math is not the best so understanding the 'Trajpar' equation etc is a bit taxing on my already wheezing brain. I've been practising and trying to understand this for over a day now. (don't tell my boss)

I came across a post quoting (Denavit-Hartenberg aproximation) ( 9 homogeneus matrix). This is new to me but the part is exactly what i'm looking to create however the example Rar file does not work on my PC. (64-bit part on my 32-bit PC perhaps) This would have been very useful to see how it was created using 'edit definition' maybe? Also the equation uses symbols i cannot find the definition off anywhere i.e.

X = c1*(c2*(c3*l3+l2)+l1)-l3*s1*s3
y = c1*l3*s3+(c2*(c3*l3+l2)+l1)*s1
z = (c3*l3+l2)*s2

Should c, l, & s just be numeric values or does it mean something more?

Apologies in advance for my limited math capability but can anyone help me with this please?

Regards,

Dave...


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    1 reply

    B
    BrianMartin13-Aquamarine
    13-Aquamarine
    December 12, 2011

    Hi Dave...

    The c, l, and s are numeric values... but they also mean something more. Your best bet it to go back to the trajpar solution.

    For any SWEEP with a defined trajectory, trajpar varies from 0 to 1 down the length of the trajectory. This seems easy enough... and utterly useless at first glance. However, you can use this trajpar variable to create intricate patterns and variations along the trajectory. You've probably seem Vladimir Palffy's trajpar tutorial wherein he creates some crazy geometry with this variable. If not, check it out here:

    http://communities.ptc.com/blogs/vpalffy/2011/02/09/user-defined-springs

    If you're trying to create the coiled helical halo from the Denavit-Hartenberg discussion, you can use the matrix (which is WAY over my head), or you can use trajpar like Vladimir does.

    Here, I used trajpar to create the first coil... then used that as the basis for the second coil. I was able to sketch out my last initial "M" and use that to wrap a coil around a coil... then make it hollow! Click the image for a larger size.

    coiled_halo.png

    So Dave... what kind of shape are you after? Is it a simple coil of a coil... or something more complex? What shape is your filament?

    Thanks!

    -Brian

    M
    MeDaveo1-VisitorAuthor
    1-Visitor
    December 16, 2011

    Hi Brian thanks for the info.

    I managed to create the coiled coil using that (Denavit-Hartenberg aproximation) ( 9 homogeneus matrix). I noticed the equation further down the post, copy and paste and hey presto. (Thanks to Faustino Garcia)

    I've created the filament as a standard 5.6 turn Coiled coil. Nothing fancy but i'm going model it into a particular bulb used at my work for analysis etc. Problem is my rig fell over at 3.5+ turns of the large coil.

    New hardware on its way, hopefully soon.

    I see what you mean with the trajpar but i need to try a few examples 1st i think.

    I'm actually trying to create a zig zag circle now so i can sweep a tread like pattern in a tyre. Any ideas?

    Regards,

    Dave

    J
    John.Pryal1-Visitor
    1-Visitor
    December 20, 2011

    Hi David,

    as far as your tread like pattern is concerned, i'm not 100% sure i understand your requirements, but have you considered using Toroidal Bend? (insert, advanced, toroidal bend). I could be barking up the wrong tree here, but i saw the words tread & tyre, & i have seen a tutorial somewhere in the past using this technique to create such a thing.

    Regards

    John

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