topic Re: Sketch dimension in increments based on the number of increments in a driven dimension in Fusion Design, Validate & Document Forum

Sketch dimension in increments based on the number of increments in a driven dimension

kearlyHQ5QE — Fri, 26 Sep 2025 11:09:49 GMT

I am attempting to create a sketch that the length of a line is specified in increments, based on how many of those increments are in another driven sketch dimension. The first attachment shows the fully constrained sketch.

The 3.2" vertical line is the line which is intended to be at least 0.25" longer (in increments of 0.1") than the driven dimension d5 (1.7506) where the 60 deg angled line, intersects the vertical line.

A user parameter "incr" was created ceil(( d5 + 0.25 in ) / 0.1) to determine how many 0.1 increments exists within the driven dimension d5. In this case the value of incr is 21.

The length dimension of the vertical line is then changed to incr*.1 as shown in the second attachment.

Upon entering the length dimension, the value is updated to 2.1 as expected, however, the sketch becomes unconstrained, and the actual length of the vertical line itself does not change to 2.1 as can be seen from inspection in the third attachment.

Is there a way to get the actual length to the computed value of the expression automatically and the sketch stay constrained? Any help would be greatly appreciated.

Thank you

Re: Sketch dimension in increments based on the number of increments in a driven dimension

davebYYPCU — Fri, 26 Sep 2025 11:57:12 GMT

If Incr = 21 it would be Unitless. (plain number)

for D7 to = Incr * .1 will fail because it needs the unit added.

use Incr * 0.1 in

Because D7 is looking for a unit (inch) parameter you have to multiply by using 0.1 inch in the formula

(I am a metric guy)

Might help....

Re: Sketch dimension in increments based on the number of increments in a driven dimension

kearlyHQ5QE — Fri, 26 Sep 2025 18:16:53 GMT

Thank you for the reply, the solution works as long as the increment parameter is specified explicitly in the Modify Parameters dialog as in the first attachment.

However, if the increment value determination is made an expression, i.e., the incr2 function of the driven dimension d7 in the second attachment, and the value of d5 is changed which drives the value of d7, the value of d8 changes in the sketch to 1.9 in the example in the second attachment, but note that the actual length of the line is still 2.1.

Not sure how the value could change but the actual length does not?

Re: Sketch dimension in increments based on the number of increments in a driven dimension

davebYYPCU — Fri, 26 Sep 2025 20:16:57 GMT

I can’t explain that., other than maybe the driven dimension fails with the ceil function. @jeff_strater ?

Re: Sketch dimension in increments based on the number of increments in a driven dimension

jeff_strater — Fri, 26 Sep 2025 22:34:32 GMT

I know that the ceil and floor functions have always had problems. The good news is that I just saw a bug fix report a couple of weeks ago that indicated that these had been fixed. I have no idea, anymore, when those fixes will see daylight, but they are coming.

Re: Sketch dimension in increments based on the number of increments in a driven dimension

kearlyHQ5QE — Fri, 26 Sep 2025 22:52:58 GMT

Thank you, been trying to diagnose this problem with all kinds of simple test cases with no success within current functionality. If you could reply to this thread in case you hear of the bug fix being implemented in a future release it would be much appreciated.