Loft is giving me fits.

David_M441

I'm brand new at Onshape, and 3d modeling in general. I'm just poking around trying to get a feel for it, considering using it for some cnc routing soon.

Anyway, I though a neat project would be to make a model of a greenland paddle (http://www.qajaqusa.org/QK/makegreen2.pdf)

Its got lots of interesting shapes, and I had tried to do it in SketchUp previously and couldn't do it. I'm basically trying to sketch cross sections along the paddle shape and join then using the Loft tool, which seems to me like it should work. It's been fighting me every step of the way, though. I thought I finally had it whooped with guides, but this latest issue has me stumped.

It won't use half my guides for this particular loft. The error is "All guides should intersect each profile boundary." I cant figure why these guides are any different than the many others that do work. Any advice?

https://cad.onshape.com/documents/2a77bf77a3f17ee3747f612e/w/841bb73cf668efcadf8bbfa7/e/c5bcf47731205aa214c5ad6b

David_M441

I think I found the issue/a solution. For some reason, as I'm putting in the guides using the "use" tool, some of the points don't register on the point I'm clicking. Instead, the new point comes up offset in a random direction a tiny bit, and won't let me use a line attached to it as a guide. I have not been able to figure out why this happens, or get it to not happen on the points it happens to..

I cleaned up my sketches some then put my guides on different planes and got pretty close to fixed. Theres still a little twist on one side I need to iron out. I hope these functions get quicker and easier with practice, because this seems like a ridiculous amount of effort for a pretty simple model.

jakeramsley

Hi david_menke574,

I took your design and applied a bit of a different method to it.  Instead of doing a bunch of effort to line up planes and 2D lines, I opted to use 3D Fit Splines (https://cad.onshape.com/help/Content/3d_fit_spline.htm), folders, visibility, and cross-selecting to make the guides.

My public document can be seen here:
https://cad.onshape.com/documents/1d3090745f1056af9196e151/w/d1c95469b1efeb89698fca7f/e/8539bc6afe2710ad97c7ced0

I set up the bare bones structure of the profiles and guides first:


I grouped all of the profiles and guides in individual folders.  This way I could easily control the visibility (this will be useful later).


Making the guides, all I did was select the from point and two point on the vertex using 3D Fit Spline


As I needed to make 24 of them to mimic the guides you had, I used the Shift + Enter shortcut key to repeat the command and reduce mouse milage.  This will submit the current feature and open up a new feature of the same type (in this case, 3D Fit Spline).
https://cad.onshape.com/help/Content/dialogs.htm?Highlight=shift%20+%20enter

This allowed the guides to be made quickly without needing to setup planes, project points, and add constraints.


I then started a loft command, select the two profiles that I wanted to bridge between.  I then put focus in the guides field, angled the camera away a bit and used cross-selection to select all the guides, which is done by dragging the box right-to-left.  This will select all of the curves that are anywhere in the selection.





I then repeated this process for each loft then followed your process to revolve and mirror at the end.

David_M441

I think I found the issue/a solution. For some reason, as I'm putting in the guides using the "use" tool, some of the points don't register on the point I'm clicking. Instead, the new point comes up offset in a random direction a tiny bit, and won't let me use a line attached to it as a guide. I have not been able to figure out why this happens, or get it to not happen on the points it happens to..

I cleaned up my sketches some then put my guides on different planes and got pretty close to fixed. Theres still a little twist on one side I need to iron out. I hope these functions get quicker and easier with practice, because this seems like a ridiculous amount of effort for a pretty simple model.

jakeramsley

Hi david_menke574,

I took your design and applied a bit of a different method to it.  Instead of doing a bunch of effort to line up planes and 2D lines, I opted to use 3D Fit Splines (https://cad.onshape.com/help/Content/3d_fit_spline.htm), folders, visibility, and cross-selecting to make the guides.

My public document can be seen here:
https://cad.onshape.com/documents/1d3090745f1056af9196e151/w/d1c95469b1efeb89698fca7f/e/8539bc6afe2710ad97c7ced0

I set up the bare bones structure of the profiles and guides first:


I grouped all of the profiles and guides in individual folders.  This way I could easily control the visibility (this will be useful later).


Making the guides, all I did was select the from point and two point on the vertex using 3D Fit Spline


As I needed to make 24 of them to mimic the guides you had, I used the Shift + Enter shortcut key to repeat the command and reduce mouse milage.  This will submit the current feature and open up a new feature of the same type (in this case, 3D Fit Spline).
https://cad.onshape.com/help/Content/dialogs.htm?Highlight=shift%20+%20enter

This allowed the guides to be made quickly without needing to setup planes, project points, and add constraints.


I then started a loft command, select the two profiles that I wanted to bridge between.  I then put focus in the guides field, angled the camera away a bit and used cross-selection to select all the guides, which is done by dragging the box right-to-left.  This will select all of the curves that are anywhere in the selection.





I then repeated this process for each loft then followed your process to revolve and mirror at the end.

David_M441

Hey, Jake

Thanks for your detailed explanation on this. I restarted this project from scratch this morning, and with your advise I finished the model in 1/4 the time with much more consistent results. Maybe I can learn this thing after all!

jakeramsley

Hi david_menke574,

That's good to hear.  To me, CAD has always been a learned skill that you improve with practice and learning new approaches.  

If you haven't already, I would recommend checking out our learning center and following some of our self-paced courses:
https://learn.onshape.com/

We also have some instructor lead training offerings, for a price, that you can register there.