Need help how to model this part

michael_mcclain

Hello all, 

I have to redraw this old model of a shifter boot for a new manufacturing process and I just can figure out how it was modeled before and how to begin to model it new.

https://cad.onshape.com/documents/9264a7446ebc32f0a3f486ca/w/611841cb3bcefcddf7732348/e/75ae4918184800288fca15d4

The goal is to match the inner dimensions closely enough and to set up the model for variable thickness to allow flexibility with semi-rigid materials.

I believe the original model was done in Creo, but I am not sure as I only have a Step file.

Thank you for any help and modelling tips. I just can't seem to figure this one out.

jakeramsley

My thought is to make everything as a surface and thicken at the end.  I split up the part into four separate sections and labeled them in the order I'd make them.

#1 seems consistent cross-sectionally throughout, so I would sketch the cross-section, sketch a path and sweep
#2 is more variable, so I'd want a path (or paths) that would mimic it.  To me, the path looks like a rectangle with fillets and a slight up/down section on the sides.  I would sketch both and use projected curves to get the paths.  I would then use the edges of the model and the path and use either a fill or a loft between them.
#3 pretty simple, looks to be revolved
#4 looks lofted between the top edge of our sweep and the bottom edge of the revolve

NeilCooke

@michael_mcclain - it's not dimensionally accurate, but near enough

https://cad.onshape.com/documents/7b4b0dd908d65a369f51ba06/w/e70035bdc1693f196f26fa31/e/a6f894a27a20ba9a4a899a92

NeilCooke

Doesn't look overly-complicated - how accurate does it need to be? For example, the sides are not straight/parallel.

michael_mcclain

It doesn't have to be point for point accurate. I am not sure of some of the design intent from the original model. I noticed that some things aren't symmetrical and don't seem to line up in a way that makes sense to me.

I can make the simple prismatic version of the part, but when it comes to all the fillets and rounds in odd places I am at a loss. There is also the base which is warped in a way that I can't figure out how to replicate it.

I feel like my modeling brain is blocked on this particular model and I need a gentle nudge in the right direction to begin it.

jakeramsley

My thought is to make everything as a surface and thicken at the end.  I split up the part into four separate sections and labeled them in the order I'd make them.

#1 seems consistent cross-sectionally throughout, so I would sketch the cross-section, sketch a path and sweep
#2 is more variable, so I'd want a path (or paths) that would mimic it.  To me, the path looks like a rectangle with fillets and a slight up/down section on the sides.  I would sketch both and use projected curves to get the paths.  I would then use the edges of the model and the path and use either a fill or a loft between them.
#3 pretty simple, looks to be revolved
#4 looks lofted between the top edge of our sweep and the bottom edge of the revolve

michael_mcclain

@jakeramsley this is exactly the nudge I need! I'll try some of these ideas out later and see what solution I come up with.

I had also thought to surface model and thicken later, but achieving the various surfaces was the part I just couldn't wrap my brain around.

Thank you for the great help!

NeilCooke

@michael_mcclain - it's not dimensionally accurate, but near enough

https://cad.onshape.com/documents/7b4b0dd908d65a369f51ba06/w/e70035bdc1693f196f26fa31/e/a6f894a27a20ba9a4a899a92

bruce_williams

@michael_mcclain thanks for posting.  We all can benefit from the challenges.

@NeilCooke
what a great approach!  mastery using the palette of Onshape tools.  I especially like the base sketch with mate connectors used for later sketches and the projected curve for bottom.  A lot to learn from this one!

NeilCooke

@bruce_williams - after your very generous praise, I went back to marvel at my model only to notice that there was some dodgy faces at the bottom. Took a few goes to rectify the issue, but adds some more tricks to the model. Please use the latest version. Thanks!

owen_sparks

Now make it bend...

michael_mcclain

@NeilCooke Thank you very much!

I went through your model and I have to say it is some great work. I see a few tricks I will have to incorporate into my workflow. I would have never thought of the projected curve for the sweep path. I forgot that tool existed.

This is exactly what I needed and I learned a few new things along the way. Onshape forum and support is the best!

P.s. @owen_sparks If you want to have a go and throw in some flexibility then be my guest. Might as well throw in the whole shifter and linkage while you are at it haha.

larry_hawes

I went through each feature one by one and was amazed at the approach. Might have actually learned something but most was way over my head. Still very nice work Neil.