giha woo: constrained ball
giha woo: constrained ball
aug 09, 2010

giha woo: constrained ball

‘constrained ball’

‘constrained ball’ is a drawing aid created by korean product designer giha woo. once attached to the pen, this device helps to draw straight lines without using a ruler. normally, a ball point pen rolls freely in accordance with the ball located at the tip of the pen. however, this writing tool prevents winding lines by helping to move the ball in one direction only. using the installed measuring wheel indicated on the product, users can draw the exact desired line length in both a horizontal and vertical direction, as well as strokes in 45 degree angles.

giha woo: constrained ball

giha woo: constrained ball the mounting area is made with a flexible rubber material helping it adhere to the attached pen.

giha woo: constrained ball

giha woo: constrained ball measurement of line is indicated on the product

giha woo: constrained ball

giha woo: constrained ball

  • How do I buy this??

  • I think this is a great tool as I do art work and sign writing and sometimes rulers slip or get in the way. I know I would use it quite often

  • This is actually a really good idea – I know that sometimes when I’m inking a straight line with a ruler, the ruler will smudge the lines and I’ll have to redo the page all over again. so in these kinds of circumstances having an aid to draw a straight line that won’t impact the line itself would be fantastic!

  • Hi. could you please let me know how can i get the constrained ball

    Thank you

    Ashraf Hendawi
  • Is this item commercially available for purchase?

  • oh my god i need one of this!

  • So i have to change my grip to use it?
    Idea has potential.

  • go straight?
    if really… perfect!

  • love it!
    want one!

  • very great idea !!!!!!

    Esraa al sharaa
more comments

have something to add? share your thoughts in our comments section below.
all comments are reviewed for the purposes of moderation before publishing.

comments policy

(6 articles)


a diverse digital database that acts as a valuable guide in gaining insight and information about a product directly from the manufacturer, and serves as a rich reference point in developing a project or scheme.

design news

keep up with our daily and weekly stories
508,090 subscribers
- see sample
- see sample
designboom magazine