CAD Forum

Currently we are introducing more & more cut outs to our parts because we have to save weight.

This is what the cutouts look like: So the basic pattern is a 4x5 pattern of a cutout. Looks like a classic candidate for a variable pattern, but - the MOST important measurement though is the distance BETWEEN the cutouts (yellow) & the distance to the EDGES of the part (pink is off limits for any cutout): Note: This is NOT symmetrical! The line in 'the middle' is a little bit offset.

Is there a good way to do this?
I feel like variable pattern SHOULD be the way - but I cannot figure out how to dimension in between the instances correctly.
Am I missing something?

Edit: this may be interesting question for @Alin , I guess. If you haven't solved it already...

does the rectangle that's not in phantom lines count as a cutout?

Just thinking out loud here, why not have a variable that defines the pink cutout so that you can then work your phantom line cutout patterns inside that defined area, then you could most likely use variable patterns, though I've never used them. I'm just wondering how you're going to define the yellow spots because the phantom line cutouts differ and because of this, the yellow spacing also differs. Though, if the pattern is always a 4 x 5 pattern, then that makes it more simple, just have to think of the required "equation"

Edit: Also depends of how variable a variable pattern can be, because you have different shapes all over the X and Y pattern

berg_lauritz wrote: ↑Wed Mar 02, 2022 2:42 pm So the basic pattern is a 4x5 pattern of a cutout. Looks like a classic candidate for a variable pattern, but - the MOST important measurement though is the distance BETWEEN the cutouts (yellow) & the distance to the EDGES of the part (pink is off limits for any cutout):

What you state right there sounds like all the design intent needed to define a sketch. I already see the sketch you've made. Is that not good enough?
Or, are you trying to make a library feature part (or something) that you can impose upon many different parts?

Question:

Would it be easier to "add the ribs" to a much larger cutout, rather than add the cutouts to a solid piece?


Here is a simplified example of what I mean.

Tom G wrote: ↑Wed Mar 02, 2022 3:54 pm What you state right there sounds like all the design intent needed to define a sketch. I already see the sketch you've made. Is that not good enough?
Or, are you trying to make a library feature part (or something) that you can impose upon many different parts?

Yes, I can make it as a sketch - but I thought there might be a better way/patterned way to do this because it's a lot of sketch relations & measurements that are "patterned" in a way.

AlexLachance wrote: ↑Wed Mar 02, 2022 2:53 pm does the rectangle that's not in phantom lines count as a cutout?

It is a cutout. But that cutout has a different design intent than the weight savings & that is why I excluded it.

AlexLachance wrote: ↑Wed Mar 02, 2022 2:53 pm Just thinking out loud here, why not have a variable that defines the pink cutout so that you can then work your phantom line cutout patterns inside that defined area, then you could most likely use variable patterns, though I've never used them. I'm just wondering how you're going to define the yellow spots because the phantom line cutouts differ and because of this, the yellow spacing also differs. Though, if the pattern is always a 4 x 5 pattern, then that makes it more simple, just have to think of the required "equation"

Edit: Also depends of how variable a variable pattern can be, because you have different shapes all over the X and Y pattern

Yes, I can make it as a variable pattern, BUT then I have to sacrifice design intent for it as far as I know, because I can not use the dimensions (yellow) in between to define it. I can easily go by X/Y position combined with length/width of the cutout - that's per instance though. So if I slightly change the position of the pink area or the position of the horizontal/vertical bracing (yellow) I have to change all measurements accordingly: Or do I simply have to link some dimensions for a linear pattern to achieve this?
Something like
[center to center pattern distance] = [pattern length/width] + [distance in between(yellow)]

But then again that is not very easy to understand nor does it look neat....
I wish there was something like a variable 'linear' sketch pattern that you could define....

Edit:

DanPihlaja wrote: ↑Wed Mar 02, 2022 4:15 pm Question:

Would it be easier to "add the ribs" to a much larger cutout, rather than add the cutouts to a solid piece?


Here is a simplified example of what I mean.
image.png
image.png

Maybe in this case it's a good idea. I will give it a try on some parts.
Although the width varies ever so slightly for those 'ribs'.

berg_lauritz wrote: ↑Wed Mar 02, 2022 2:42 pm Currently we are introducing more & more cut outs to our parts because we have to save weight.

This is what the cutouts look like:
Screenshot 2022-03-02 131713.png

So the basic pattern is a 4x5 pattern of a cutout. Looks like a classic candidate for a variable pattern, but - the MOST important measurement though is the distance BETWEEN the cutouts (yellow) & the distance to the EDGES of the part (pink is off limits for any cutout):
Screenshot 2022-03-02 132826.png
Note: This is NOT symmetrical! The line in 'the middle' is a little bit offset.

Is there a good way to do this?
I feel like variable pattern SHOULD be the way - but I cannot figure out how to dimension in between the instances correctly.
Am I missing something?

Edit: this may be interesting question for @Alin , I guess. If you haven't solved it already...

If the general goal is just to decrease weight, one idea that comes to mind is to split your part so that the off limits areas are a separate body:
Then create a sketch with a pattern in it that you can tweak: Then use the sketch to cut only the body that isn't off limits: Finally combine the bodies back together:

JSculley wrote: ↑Wed Mar 02, 2022 4:39 pm If the general goal is just to decrease weight, one idea that comes to mind is to split your part so that the off limits areas are a separate body:

image.png
Then create a sketch with a pattern in it that you can tweak:
image.png
Then use the sketch to cut only the body that isn't off limits:
image.png
Finally combine the bodies back together:
image.png

That was my first idea too because I can loosely define my sketch pattern first & then adjust it to my needs & even change the instance count fairly easily. I can also spot interferences fairly easy.

But modifying it is painful because I cannot vary the distance between instances:

berg_lauritz wrote: ↑Wed Mar 02, 2022 4:57 pm That was my first idea too because I can loosely define my sketch pattern first & then adjust it to my needs & even change the instance count fairly easily.
Screenshot 2022-03-02 155100.png

I can also spot interferences fairly easy.

But modifying it is painful because I cannot vary the distance between instances:

Screenshot 2022-03-02 155458.png

Why not take @JSculley's idea and slightly tweak it?

1) Model the off-limits areas as a separate body.
2) Create a sketch with one profile.
3) Cut.
4) Pattern the cut feature using Linear Pattern with Skip and Vary options. You can even resize the cutouts with it.
5) Combine.

Edit: fixed order mistake

Honestly, even though this doesn't really apply to my line of work, this is a very interesting topic!

I'd probably go for an equation, but I can understand what you mean, that it's not really simple to read and understand afterwards, which is why I'd suggest having an external file, such as a Word, that explains how to drive these and what the equation represents with each variables also.

berg_lauritz wrote: ↑Wed Mar 02, 2022 4:57 pm But modifying it is painful because I cannot vary the distance between instances:

Instead of sketch pattern use feature pattern and you can use vary dimensions between the instances.

Interesting topic, I would take a simpler approach as @JSculley mentioned plus honeycombs.
Best weight saver pattern and also easy to apply everywhere: