Can't create "No Units" parameter when expressing other parameter in "mm"

[NVNDO]

My intention is the following:

I have created a Body that goes along a diameter (now 500mm) 

I used the "Circular pattern" tool to create (14 pieces) of it. 

Now I want to be able to change the diameter and that the "pieces" multiply accordingly and maintain their size using the simple approach of creating the following parameter: (diameter/100*3) preferably (diameter/100*3-1) as it should be "14" - and use this as value for the circular pattern tool.  But it does not work.

 

I could give you at least 20 screenshot of different approaches that all didn't work, but that will probably not help anyone, but in summery, what I noticed is the following PROBLEM:

One can NOT create a parameter with "No Units" using a parameter "with units (mm)" as expression.  

 

When I change from "No Units" to "mm" all of the sudden the calculation works.

 

QUESTION: How can I use a parameter "with units" as expression (to calculate something) when the outcome should have "no units".  to use as value for example in "Circular pattern"

I really hope I explained this well enough and I'm hugely sorry if this is a stupid question, but for me it does not make sense on why its not working. 

PD: I tried to get this working for the last 2 hours and I have not been able to. I would say I tried everything.

From simple to complicated math, renaming, changing units, using google and ChatGPT.. but nothing.

[HughesTooling · Accepted solution]

You can cancel a parameter's unit by dividing by its units. So if you have a parameter Length and its units are mm just use Length/mm to make it unitless.

[g-andresen · Accepted solution]

Hi,

divide by 1mm!

günther

[NVNDO]

Well... that was easy.

Is it just me, or isn't there any logic behind this?
Now that I know I know (that's one thing), but its not something one would or could come up with on his own I would say.

Funny enough, after posting I thought.. there must be a way of converting values - but you guys answered so quickly, I could not even google that fast.

Thank you so so much!!

[HughesTooling]

@TheCADWhisperer Always says this is taught in basic maths lessons. Don't remember it myself and maybe before my time. It is standard for all the solid modeling programs I've used for the past 20+ years though.

[NVNDO]

To my defenece, I was always very bad in maths. Numbers is not my thing and Fusion reminds me of that all the time. ^^

[g-andresen]

Hi,

Multipliers represent the ratio of 2 lengths, for example.

günther

[NVNDO]

To my "not" surprise my initial intention does not work. Since then I'm again googling and using ChatGPT, but apparently I'm hitting my and their limits. I'm just to dumb for this.

My initial idea was: to create a piece of track that interlocks with each other and create a circle. (I managed that)

Then I wanted to be able to change the diameter of the circle and have the pieces multiply accordingly (maintaining their outer edge to edge width of 120mm and only changing their outer angle.

I just figured out, that this is not possible as the pieces will in-evidently change in size.

So my next approach was to just multiply the pieces in circle and have the circle to grow depending on the pieces. 

But I'm just not smart enough... 

This was ChatGPTs approach, but Fusion keeps changing the parameter and adding *1deg

I sincerely feel bad asking all this.. I maybe just think about a different approach. 

[g-andresen]

Hi,

Is that what you want to achieve?

To avoid misunderstandings, please sketch the arrangement (possibly by hand) and mark the fixed and variable dimensions.

günther

[HughesTooling]

Is this what you want or is the width the arc length?

[NVNDO]

To my "not" surprise my initial intention does not work. Since then I'm again googling and using ChatGPT, but apparently I'm hitting my and their limits. I'm just to dumb for this.

My initial idea was: to create a piece of track that interlocks with each other and create a circle. (I managed that)

Then I wanted to be able to change the diameter of the circle and have the pieces multiply accordingly (maintaining their outer edge to edge width of 120mm and only changing their outer angle (maintaining a closed loop).

I then figured out, that this is not possible as the pieces will in-evidently change in size as they will never be an exact division of the diameter I wish to have.

So my next approach was to just multiply the pieces in circle make the circle grow depending on the amount of pieces and call it a day. Well..it seems I'm just not smart enough.

May I ask you @g-andresen to have a look at this..?

I sincerely feel bad asking all this.. but I just don't know what else do to..

[HughesTooling · Accepted solution]

Avoid using sketch patterns, keep it simple and just pattern the body. Always try and fully constrain all the sketches so you get predictable changes when you modify a parameter.

See attached file. Apart form simplifying the sketches I need to add Amount for the count in the circular pattern.

[g-andresen]

Hi,

---

@NVNDO wrote:

Then I wanted to be able to change the diameter of the circle and have the pieces multiply accordingly (maintaining their outer edge to edge width of 120mm and only changing their outer angle (maintaining a closed loop).

---

Forget Chat GPT and follow the laws of divided circles.

You cannot change the diameter of the circle for identical elements without changing the segment length.

günther

[NVNDO]

That's why I wrote "I then figured out, that this is not possible as the pieces will in-evidently change in size as they will never be an exact division of the diameter I wish to have." afterwards ^^

[NVNDO]

How on earth....? 😲 

You basically made the sketch much simpler and just divided the whole into the required parts by adding.  "( 360 / Amount ) * 1 deg" 

That seems so simple but I would have never ever come up with this. 

Thank you so much!! Seriously...  Thank you.