Expressions and using Power Duplicate

[Kiarian]

Can someone help me out here? I create a circle (10px by 10px) with a thickness of 2, CTRL+J to copy, go into the Transform box and type +8 in the W: and H: section. So I now have my duplicate circle (increased 8 pixels both in the width and height). OK, so all I want to do now is to power duplicate and keep pressing CTRL+J however many times I want to make these circles, each one 8 pixels larger than the previous. Isn't the expression of +8 in both the W and H correct?
I'm not getting each circle +8 pixels larger than the last. 

[Old Bruce]

The duplication is 180% not 8 pixels. I don't think that we can specify a fixed unit increase/decrease. When you think about decreasing the size this using the times/percent instead of a fixed unit of measure makes sense. Start with a ten pixel diameter circle and decrease it by 8 pixels and repeat, what does a negative 6 pixel wide object look like?

[Alfred]

1 minute ago, Old Bruce said:

what does a negative 6 pixel wide object look like?

The same as a positive 6 px wide object, but flipped horizontally?

[lepr]

Power Duplicate scales by the ratio of the first duplicate's size to the original object's size. It has no knowledge of how the duplicate's size came to be.

Currently, there is no tool for repeatedly duplicating with application of an expression such as "w += 8; h += 8" which would increment the width by 8 and height by 8 for each iteration, but it has been requested.

[Kiarian]

5 minutes ago, Old Bruce said:

 I don't think that we can specify a fixed unit increase/decrease.

Ahh, I was typing a combination of either just 8, or 8px to see if I could specify a unit.

[Alfred]

1 minute ago, Kiarian said:

Ahh, I was typing a combination of either just 8, or 8px to see if I could specify a unit.

You can specify a unit if you want to, but it won’t help! Entering +6pt when your document units are pixels will give you the same result as entering +8px (i.e. it will still end up being treated as if you’d specified a scaling amount).

[gary danang]

So I am trying to replicate lines at 4mm intervals.. but every duplication results in a slight large increment - surely this is a bug.. ?  

[carl123]

1 hour ago, gary danang said:

So I am trying to replicate lines at 4mm intervals.. but every duplication results in a slight large increment - surely this is a bug. ?  

I don't think it has been logged as a bug but currently "By design". There may be an improvement request in the pipeline somewhere.

For now, you can power duplicate your lines at any interval then use the Distribute option in the Alignment button pop-up to space them at exactly 4mm intervals

[gary danang]

Thx Carl,, yes will resort to that.... interestingly it does not incrementally increase when you rotate....  may not be a bug but it is definitely a lazy

 oversight

[Pšenda]

11 hours ago, gary danang said:

So I am trying to replicate lines at 4mm intervals.. but every duplication results in a slight large increment

Example? I have no problem with that.

[gary danang]

hmmmmm,, thx... thats strange then

 

[Old Bruce]

We have to be careful with the duplicate then Move and or Rotate (whatever). If I inadvertently reselect the duplicated object then the duplicate command will just place the third in the same spot as the second, not move/rotate it.

[R C-R]

3 hours ago, Pšenda said:

Example? I have no problem with that.

Same here on a Mac. The 21 lines in power dup.afdesign were made using power duplicate. Only after doing that did I set a 4 x 4 mm  grid & then snap the lines to the grid to show that the spacing was uniform.