How can I extrude around the outside of a round face?

brian_sweet

I have a basic ring the I would like to remove a diamond shape pattern all the way around it.  I was able to do one with a tangent plane.  tut I am at a lose how to do that many times around it.  I thought multi plain might be the answer, but either I am doing it wrong or it isn't meant do what I am trying to do.  

Here is my start:

https://cad.onshape.com/documents/665c0ed5ebd690d47908381b/w/8d731be1cdd8f44a59e9eede/e/0157ae2f40c73d8a1d0e4ec2

As an example, let's say I want to have12 diamonds around the ring evenly spaced.  

Any help to this newbie would be greatly appreciated. 

Prachi

Feature pattern.

Prachi

Little more work on this example but the holes don't overlap like a straight extrude.
https://cad.onshape.com/documents/1249a62cc918c7b9b008fbec/w/416e108a56778eeea8823df6/e/8252077a16e0a785453855ae

matthew_stacy

@brian_sweet, a few key mathematical tools for this endeavor are:

1. Circumference = PI * D
   
2. Arc_length = R * Theta (with the angle specified in radians)
3. Use the floor() function to truncate any calculated pattern count to a whole number (i.e. round down)

How to implement the math functions depend on what your trying to do.  Explicitly defining a variable for every parameter overconstrains the problem and will result in mathematical or geometric conflicts.  For example #Ring_size, #Lattice_width, and #Diamond_size can potentially conflict with one another.  #Pattern_Count has the potential to further conflict with these.  Imagine red ink in your feature-tree or lattice lofts overlapping / spilling off the top or bottom.

You will have to choose a small number of INDEPENDENT variables and allow all other parameters to float (automatically scaling according to the specified independent variables).

By way of example, here is a simplified version of your model with the upper and lower triangle lofts omitted for clarity:  https://cad.onshape.com/documents/02f15cc45132085896aa6f5b/w/9c9fc970396d7e20ae17cee1/e/8c8c76e0ef28eb38b5c8f346.  Most of the features (Extrude 1 height, pattern count) scale directly from #Diamond_size. 

Happy modeling!

Prachi

Feature pattern.

brian_sweet

Thank you, that was so simple.  Thanks for giving me the opportunity to learn

Prachi

Little more work on this example but the holes don't overlap like a straight extrude.
https://cad.onshape.com/documents/1249a62cc918c7b9b008fbec/w/416e108a56778eeea8823df6/e/8252077a16e0a785453855ae

brian_sweet

That's even better.  I was messing around with the file, but here is the design I am looking for using your loft idea:
https://cad.onshape.com/documents/315f6616a46a1eceda8a161b/w/e8f39b6733b49dc2eaa1453b/e/38cac24dabd0a93aea4b98db

Not sure you you want/can to provide me any more additional advice, this is more a mathematical calculation help (My college Trig courses are long wiped from memory...lol). 

When doing the circular pattern with this design, I am tying to figure out how to adjust the pattern count to the lattice spacing and to make the spacing even. With pattern count at 25 and spacing at 2 it looks close, but you can see the spacing before then next patter starts is a little bigger. 

My goal would be to be able to change the diameter for a larger/smaller bracelet size and have the lattice spacing even. 

And Lastly thank you for your help.  I started 3d printing a year ago and want to design things, tinker cad was to basic and OnShape had a bit more learning curve.  But I can't tell you how much (even when I get frustrated when it doesn't work) I love working on designs in OnShape

matthew_stacy

@brian_sweet, a few key mathematical tools for this endeavor are:

1. Circumference = PI * D
   
2. Arc_length = R * Theta (with the angle specified in radians)
3. Use the floor() function to truncate any calculated pattern count to a whole number (i.e. round down)

How to implement the math functions depend on what your trying to do.  Explicitly defining a variable for every parameter overconstrains the problem and will result in mathematical or geometric conflicts.  For example #Ring_size, #Lattice_width, and #Diamond_size can potentially conflict with one another.  #Pattern_Count has the potential to further conflict with these.  Imagine red ink in your feature-tree or lattice lofts overlapping / spilling off the top or bottom.

You will have to choose a small number of INDEPENDENT variables and allow all other parameters to float (automatically scaling according to the specified independent variables).

By way of example, here is a simplified version of your model with the upper and lower triangle lofts omitted for clarity:  https://cad.onshape.com/documents/02f15cc45132085896aa6f5b/w/9c9fc970396d7e20ae17cee1/e/8c8c76e0ef28eb38b5c8f346.  Most of the features (Extrude 1 height, pattern count) scale directly from #Diamond_size. 

Happy modeling!

brian_sweet

This was so helpful.  MANY THANKS!