How will you do this -- Removing Undercut

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zwei
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How will you do this -- Removing Undercut

Unread post by zwei »

Would like to get some opinions on whether is there a better way to do this...

Assuming we have a imported surface.
image.png
If we would like to remove the undercut on the side surface and apply a 1 deg draft (without affecting much of the original surface)
At the same time, we also want to maintain the lower front edge profile (do not change the lower edge length)
* The top front edge profile can be change if required
image.png
What will be the best approach in changing the imported surface?
I manage to modified the surface by splitting and drafting a copied surface and use Move Bodies to re-attach the surface to the lower front edge profile...
image.png
image.png (8.44 KiB) Viewed 2354 times

Just wondering is there a better way to approach this. :?
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CurveSurface-Ex1.STP
(60.37 KiB) Downloaded 147 times
by matt » Sun Aug 08, 2021 1:22 pm
Zhen-Wei Tee wrote: Sun Aug 08, 2021 12:37 pm I think there is some kind of misunderstanding here...

I would like to remove the undercut region (boxed in rectangular) by applying a draft of 1deg (not remove the rectangular region entirely)

Hope this clear things up
It would be helpful if you pointed out the direction of pull, and what you mean by side, top and bottom. I'll assume you have it the way I show it:
image.png
The Split Line has an option to split at the draft angle, which produces this:
image.png
This is the setup. I'm using the Front plane as the direction of pull, highlighted in the image below. The red surface is one degree or more up. The edge between the gray and yellow surfaces is the zero degree parting line. Blue is one degree or more down.

"Undercut" requires a frame of reference. The blue and yellow faces are undercut from the up direction, and the red and gray faces are undercut from the down direction.

What exactly are you trying to do? If you're trying to create a drafted surface from an edge, use the Ruled surface.
image.png
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Maha Nadarasa
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Re: How will you do this -- Removing Undercut

Unread post by Maha Nadarasa »

Do you want only to remove rectangular potion.
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zwei
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Re: How will you do this -- Removing Undercut

Unread post by zwei »

Maha Nadarasa wrote: Sun Aug 08, 2021 11:49 am Do you want only to remove rectangular potion.
Yes, only the rectangular area, the other area already have sufficient draft hence if possible i do not want to change the other area
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Maha Nadarasa
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Re: How will you do this -- Removing Undercut

Unread post by Maha Nadarasa »

See whether it okay.
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CurveSurface-Ex2.SLDPRT
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2.png
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zwei
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Re: How will you do this -- Removing Undercut

Unread post by zwei »

Maha Nadarasa wrote: Sun Aug 08, 2021 12:09 pm See whether it okay.
I think there is some kind of misunderstanding here...

I would like to remove the undercut region (boxed in rectangular) by applying a draft of 1deg (not remove the rectangular region entirely)

Hope this clear things up
Far too many items in the world are designed, constructed and foisted upon us with no understanding-or even care-for how we will use them.
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Re: How will you do this -- Removing Undercut

Unread post by Lucas »

Something like this, but with 1 degree?
Does the cut need to be rectangular?
image.png
Maybe you could generate a solid, make a chamfer then delete the faces:
image.png
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CurveSurface-Ex1 - split fill.SLDPRT
(129.14 KiB) Downloaded 213 times
CurveSurface-Ex1 - chamfer.SLDPRT
(155.77 KiB) Downloaded 181 times
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matt
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Re: How will you do this -- Removing Undercut

Unread post by matt »

Zhen-Wei Tee wrote: Sun Aug 08, 2021 12:37 pm I think there is some kind of misunderstanding here...

I would like to remove the undercut region (boxed in rectangular) by applying a draft of 1deg (not remove the rectangular region entirely)

Hope this clear things up
It would be helpful if you pointed out the direction of pull, and what you mean by side, top and bottom. I'll assume you have it the way I show it:
image.png
The Split Line has an option to split at the draft angle, which produces this:
image.png
This is the setup. I'm using the Front plane as the direction of pull, highlighted in the image below. The red surface is one degree or more up. The edge between the gray and yellow surfaces is the zero degree parting line. Blue is one degree or more down.

"Undercut" requires a frame of reference. The blue and yellow faces are undercut from the up direction, and the red and gray faces are undercut from the down direction.

What exactly are you trying to do? If you're trying to create a drafted surface from an edge, use the Ruled surface.
image.png
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AlexB
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Re: How will you do this -- Removing Undercut

Unread post by AlexB »

Here's my attempt. I just took the existing surface and preserved the edge that mated to the 50mm wide face (the one initially in red). I then copied the existing face and trimmed the parts that created the undercut and re-knit everything together.
image.png
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CurveSurface-Ex1.SLDPRT
(117.48 KiB) Downloaded 145 times
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zwei
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Re: How will you do this -- Removing Undercut

Unread post by zwei »

matt wrote: Sun Aug 08, 2021 1:22 pm The Split Line has an option to split at the draft angle, which produces this:

image.png
Yes, i was looking for the option to split at the draft angle, dint realize I can split the face at draft angle using split line and draft them separately

Thanks!
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Re: How will you do this -- Removing Undercut

Unread post by Cbecks Design »

Zhen-Wei Tee wrote: Wed Aug 18, 2021 7:03 am Yes, i was looking for the option to split at the draft angle, dint realize I can split the face at draft angle using split line and draft them separately

Thanks!
What does it mean, "Split the face at draft angle"?

And how do you do it? My split line feature doesn't seem to have such a thing.
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Re: How will you do this -- Removing Undercut

Unread post by Dwight »

Cbecks Design wrote: Tue Aug 09, 2022 9:08 pm What does it mean, "Split the face at draft angle"?

And how do you do it? My split line feature doesn't seem to have such a thing.
Use the Silhouette option in Split Lines.

I see there are also Silhouette Entities in SW2020+. We are still on SW2018 so I haven't played with those yet.

Dwight
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