Is it possible to scale all dimensional constraints, for example by a factor of 1000 bigger or smaller?

[mjbmikeb2]

I have a sketch that contains a triangular grid consisting of points with dimensional constraints between them to set the spacing. The triangles vary in size as I created it by surveying a plot of land using a tape measure.

I would like to make this bigger, actually a 1000 times bigger as I picked the wrong unit "mm" instead of "m".

As far as I can tell using the "modify > sketch scale" feature expands/contracts the distance between the points but erases the dimensional constraints instead of scaling them by the scale factor.

I tried using the "Modify > Change parameters" feature but that results in multiple calculation errors. Presumably to make this work you have to manually do the changes in an order that doesn't cause any constraint violations? Is that right?

I though parametric modelling was supposed to easily allow you to scale designs without losing information?

[hamid.sh.]

Is your sketch fully constrained (everything black and a red lock on its icon within browser)? If it's not scaling won't work properly for sure. That being said, scaling sketch is not a good idea in general; Make a body with current sketch and scale that. If you need sketch, you can project from the scaled body.

[dsouzasujay]

Hi @mjbmikeb2,

Can you please share the design that you have created in Fusion 360?
You can export by File>Export *.f3d file to your local drive and then Attach it here to a Reply?

[mjbmikeb2]

The problem can be seen as follows:
- Create new sketch.
- Create 3 points some random distance apart from each other.
- Apply dimensional constraints between point 1 and 2. point 2 and 3 and point 3 and 1.
- Scale the sketch using point 3 as the origin.
The constraints no longer exist.

The Change Parameters box works for simple things such as the above 3 point scenario, but once you add lots of points forming lots of constrained triangles looking something like this https://i.imgur.com/FYzbaL5.jpg ,all you see is a list in the order they were created. What you need is to see the outer most points listed first as these are the only ones that can be safely modified without causing constraint violations.

[mjbmikeb2]

Thinking about it some more I'm not sure the "outer points" Change Parameters box is going to work as you can only change one dimension at a time and with a triangular grid you need to be able to change the length of all the constraints going to a single point at the same time.

[HughesTooling]

First create a user parameter Scale and set it to 1. Now while adding dimensions to your sketch enter the dimension * Scale, for example "10*Scale". When you've fully dimensioned and constrained the sketch just edit the scale parameter to scale up\down.

Mark

[HughesTooling]

---

@mjbmikeb2 wrote:

I tried using the "Modify > Change parameters" feature but that results in multiple calculation errors. Presumably to make this work you have to manually do the changes in an order that doesn't cause any constraint violations? Is that right?

---

You might be able to use the above method with an existing design if you set up the scale parameter set to 1. Then edit all the dimension parameters and add *Scale while it's set to 1 before trying to edit the scale.

Mark

[hamid.sh.]

---

@HughesTooling wrote:

First create a user parameter Scale and set it to 1. Now while adding dimensions to your sketch enter the dimension * Scale, for example "10*Scale". When you've fully dimensioned and constrained the sketch just edit the scale parameter to scale up\down.

Mark

---

I was just trying the same thing. You beat me to it!

[mjbmikeb2]

Thanks!
I created a user scale parameter. I can scale from 1 to 2.9, but any number above that makes all the dimensions turn red. I shall investigate.

[HughesTooling]

---

@mjbmikeb2 wrote:
Thanks!
I created a user scale parameter. I can scale from 1 to 2.9, but any number above that makes all the dimensions turn red. I shall investigate.

---

Fusion does have problems sometime where a big change will make a dimension flip which side it's dimensioned. You might find you need to step up the scale in small increments. Also can you export the f3d file and share here so support can see it, it might help with tuning up the sketch solver.

I have to say I've never needed to scale a sketch as it's far easier to scale bodies at the end of the design. Do you really need to scale the sketch?

Mark

[hamid.sh.]

The file that I posted works ok, at least with scale parameter set to 100. One thing I noticed is that with having perpendicular constraint between your lines sometimes problem arises at higher scale, might be a bug, but still not sure, need to play with it more.

[mjbmikeb2]

The need to rescale at the sketch level is because I'm trying to copy and paste a bunch of point and constraints from a sketch that has dimensions in meters into another sketch which is (incorrectly) using mm and therefore there is a 1000 fold mismatch.

[HughesTooling]

I guess you're dimensioning some points from other points? I think you'll only get this to work if you dimension each point from the origin rather than have a chain of dimensions.

Mark

[hamid.sh.]

---

@HughesTooling wrote:

I guess you're dimensioning some points from other points? I think you'll only get this to work if you dimension each point from the origin rather than have a chain of dimensions.

Mark

---

I dimensioned point to point and it works with scale of 1000:

[HughesTooling]

@hamid.sh.  My reply was to @mjbmikeb2 and it sounds like they are using points only not lines so could be more chaotic! Especially if there are a lot of points.

Mark

[HughesTooling]

A couple more things that could be a problem with @mjbmikeb2 's design. Is at least one point constrained to the origin and is the sketch fully constrained. Either of these would make solving the scale quite difficult, not fully constrained would be the biggest problem.

Mark

[TheCADWhisperer]

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

If everything is "just right" it should scale with a parameter, otherwise my next thought is to delete all of the dimensions (or Toggle them to Driven), Scale the Sketch 

and add the dimensions back in (or Toggle them to Driving).

>>Check Video>> when it has completed compiling.

[mjbmikeb2]

Thanks, that seemed to work. I was able to scale my troublesome drawing all the way to a 1000 fold increase in size without it erasing the dimensions. I then changed the document units to meters and now the numbers look sensible again.
As an added bonus my dimensions have gained 11 digits of precision, for example 2.22 mm is now 2219.9999999811 mm. I'm not sure if this is a good or bad thing. They are editable so I can manually round things back to their original precision if need be.

(the video narration said "mm to inches", but I understood what you were doing)

[TheCADWhisperer]

---

@mjbmikeb2 wrote:
(the video narration said "mm to inches", but I understood what you were doing)

---

Glad you figured it out.

In the video I was referring to an alternate case, not your case.

Far more frequently someone here starts with the wrong units (inch or mm) and then post here looking for an easy way to translate the magnitude along with the units.