Scaling - I want to subtract 1/4", but how?

Is there a way to scale up/down or scale with the gumball an object’s length by entering a value of “by how much” verses having to measure the full new length I desire and typing it in? Like a subtraction or addition formula for scaling?

For example: If I have an object that is 12 inches and I want to scale it down by 1/4". Currently I have to measure the item I want to scale (here I see it’s 12 inches), so I type in the new value of 11.75". What I’m looking for is to simply subtract 1/4" WITHOUT having to measure first and then enter the new full length measurement I desire.

Do I enter -1/4" in parenthesis, braces, or is there an equation I should be using to achieve this?

I feel silly, but I’m stumped and can’t figure out how this is done in Rhino.


Hope this is what you are looking for - work out the ratio and enter that calculated value into Gumball.

Hi Brian. Thank you for the response, but not quite what I’m after. The value one enters in gumball will be the new size. I’m looking to subtract 1/4" from its full length, not scale it down to 1/4". I’m looking for a simple input feature without having to measure the original, followed by breaking out a calculator and figuring out the math.

You were so close, you only needed to add the = sign.
The Command-Line Calculator allows entering mathematical notation on the command line in response to prompts for numbers.
Type =(12-.25) on the command line to evaluate what is inside the parentheses. For scaling select the first two points then do the above at the command prompt.

You can also use the calculator with the scale command too and for more complex uses as well.
Type calc at the command line or in the panels menu open calculator,
Leave it docked or floating, when you call the scale command click the first two points, then in the calculator type 12-.25 then click the done button, the calculators content is then sent to the command line.

Sorry I don’t know if this works with gumball most likely not but it works for the scale commands if that helps.

I’ll give that a shot. Thanks so much for your help.