(I previously opened a multi question thread, which is against rules, so here's just the main question I had)

As a relatively long term Sketchup user I can't work without the line tool and the Knife tool in Blender doesn't show distance and it doesn't snap by length like the Sk-u line tool, so it's really hard to work with it.

Basically here's what I want to do, to draw a small line 20cm from ,,point Q" (random name I thought of) and then to draw a line towards the other side of the box to the point that is also 20 cm from it's version of "point Q", hopefully without using subdivision and loop tool, which both create a lot of unnecessary things and are both unprecise for what I need.

enter image description here

I was advised previosly to use the snap utilities addon, but I only want to use either Blender's own stuff or at least a freely available addon (snap utilities is 17 usd), I am a 21 year old from east europe, so I neither have (or need) a credit card, nor a paypal and I'm not in the mood to get those 2 just for a small snapping addon, I'd probably end up paying a lot more for the credit card itself..., so if there is anything free, it would be much appreciated.


4 Answers 4


Blender isn't really the right tool for doing precision 3D design, but it can be done.

You will have to do some arithmetic, but one approach would be

  • start with a view perpendicular to the face you want the edge on. In your example, it looks like that would be top orthographic, so hit NUMPAD-7
  • select the knife tool (Shortcut KKEY)
  • place the cursor on the either of the edges you want to connect and click LMB
  • type the C key
  • place the cursor on the other edge and click LMB
  • type ENTER

This will create the edge you want, but not place it where you want it.

  • type g
  • do not move your mouse
  • Go to transform panel of the properties panel and enter a value. (if the properties panel is not visible, type N to unhide it) the transform panel looks like

enter image description here

To figure out the value, here is an example, based on your image. * You appear to be adding the edge to a top face. This means that you want to set the median y value entry. * take the y value of point q and subtract 20cm from it. * enter the result.

You end up with a precisely place edge.


In this case, old-school style, no add-ons

Assuming you want your 20cm to be in the X direction (If not, you would set a custom orientation on a perpendicular edge,) and assuming your units are set to meters.

  1. K cut an edge from anywhere to anywhere on the top face
  2. GG slide the line to collapse it to the reference edge
  3. Hit GX0.2

enter image description here


Yes, the people at Blender Foundation are having a focus...

Still, in this case, I would subdivide two edges, select the new edge and press G twice. Then you can easily type in 0.8 and get exactly what you want... enter image description here enter image description here enter image description here


This might be of interest to you


S R Or this alternate method t




  • $\begingroup$ That is not necessary for the functionality that the question is about. It can be done without any add-ons with a few clicks. One can use Rip Fill function(alt+v hovering the mouse away from the edge in the direction the edge should be split), this can be followed by x, y or z to chose the axis for transform and 0.2 can be typed as numerical input during the transform operation to move it 0.2 of a meter if meters are the units set in the scene settings. $\endgroup$ Nov 28, 2018 at 10:06
  • $\begingroup$ The Line tool from this addon already comes with Blender 2.79, Just have to activate it $\endgroup$
    – Racko
    Nov 28, 2018 at 15:32
  • $\begingroup$ Yes, but this is the most basic numerical input with transform operators functionality we are talking about. It does not make much sense to use add-ons instead of it the way I see it. The very basic way to move objects in Blender works like that already. I am sure the add-on might be useful for other things, but it is not very relevant to the question. $\endgroup$ Nov 28, 2018 at 16:17
  • $\begingroup$ @Racko Interesting, could you add more info to the question about how to activate the tool? As it is it's pretty unclear, and besides, links go down over time. $\endgroup$
    – SilverWolf
    Nov 28, 2018 at 18:08
  • $\begingroup$ Yeah I updated showing how to activate it, its basically already in your Addons. Or here i.imgur.com/1wsfQRw.gif It doesnt show measurements live but it can parallel snap and draw lines which Knife tool cannot $\endgroup$
    – Racko
    Nov 28, 2018 at 18:20

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