Edge loop numerical sizes

Hi Everyone,
Brand new to Blender and Blenderartists.org. My previous experience was with Caligari Truespace many moons ago! (I’m old!)

Anyway, I can’t figure out how to find dimensions of different cross sections of objects.
For example:

-I made a cylinder, then used edge loops to create a bunch of slices.
-Made object transparent, then from side view, selected and scaled each slice in one dimension (Made a tapered end-see pic at bottom)

Now I want to go to the top view and size the slices in the other dimension so that the cylinder maintains a perfect circular cross-section down to a point.

Is there a way to see the size of the edge loop in all dimensions, so that I can numerically adjust it?

Or do I just have to “eyeball it”

Thank you in advance

For that object, I’d recommend using the screw modifier and measuring the radii with the edge length overlay in edit mode.

You can use the MeasureIt tools in the View section of the N panel. It might be an add-on but it comes with Blender so just set it up in Preferences if it’s not in the N panel. It will allow you to measure selected edges to whatever precision you want.

You don’t need to eyeball it, but it would require you to use a different workflow. Instead of scaling on one axis by a certain amount and then changing views to scale on another axis by that same amount, there is actually a way to scale on two axes at the same time. Keep in mind that this is not a workflow that works in every case, but that it works specifically for this scenario because you are modeling with your cylinder aligned to your world axes and you are wanting to scale your edge loops by the same factor. I won’t get into the difference of scaling on the local or global axes, but if you have questions on that, the Transform Control section of the manual mentions that.

Here we go:

  1. Create your cylinder the size you want at the largest point with the right amount of vertices for your project.
  2. Add your edge loops where you want them with Ctrl+R or Cmd+R. You can add them all at the same time by increasing the number of loop cuts with your mouse scroll wheel.
  3. Select your edge loop for scaling:
    A. Method 1: You can select your edge loop by holding Alt and clicking your mouse selection button (left or right whichever you have yours set to) over the edge of the loop you want.
    B. Method 2: Ensuring X-Ray is turned on in Edit Mode, align your view to where you aren’t looking at the top or bottom of your cylinder and use box select to select the vertices in your loop.
  4. Edit: Make sure your Transform Pivot Point is set to Individual Origins or Median Point. Press S to scale and then plane lock your scaling by pressing Shift+X, Y, or Z depending on the axis you want to exclude. If your cylinder was aligned with the Z axis, you want to scale your edge loop on the X and Y axis, so you’d press Shift+Z.

Now, you could still do it the way you want where you are locking your constraints to an axis based on which viewport you are looking through, but once you start constraining by explicitly typing the axes you wish to constrain by, you open yourself up to modeling from any angle or perspective while maintaining accuracy. Blender does accept numerical inputs while moving, scaling, and rotating, so you could always manually type the values you wish to scale by on each axis. If you have any further questions, please let us know! Hope this helps!

Manual reference
Transform Control: https://docs.blender.org/manual/en/latest/scene_layout/object/editing/transform/control/index.html#transform-control
Loop Cut and Slide: https://docs.blender.org/manual/en/latest/modeling/meshes/tools/loop.html#loop-cut-and-slide
Plane Locking: https://docs.blender.org/manual/en/latest/scene_layout/object/editing/transform/control/axis_locking.html#plane-locking
Pivot Point: https://docs.blender.org/manual/en/latest/editors/3dview/controls/pivot_point/index.html#pivot-point

Oh, and by the way, my first 3D model was using TrueSpace 4 - I think I have an animation I made with it laying around here somewhere. :slight_smile:

As an addendum, I don’t know exactly what I was thinking that scaling would somehow be “tied to” your viewport orientation…I guess I was thinking about moving and rotating. I also see that you have your move gizmo turned on. If you are also using the scale gizmo to scale your loops, you can use the same constraint shortcuts so you don’t have to scale twice on two axes. You just grab your gizmo handle and press Shift+X, Y, or Z and it’ll start constraining for that plane lock.

Oh, and welcome to the community, @Legios!

Thank you, I used the measure it tool. Tedious, but effective.

Hunkadoodle
Thank you, that was a lot of great information. That’s definitely the way I’ll go next time.

One question though. If I am in side view, can I still scale in two dimensions if the one of the dimensions is “coming out” out of the screen? I like the pure side view for its accuracy.

For example, in this case above, the X-axis?

Thank you for the welcome, and it’s great to meet someone that remembered Truespace! I used 3 and 4, and then tried out 7 when it became shareware.

So, yeah, there are operations that are, by default, view-dependent. Like I mentioned in my addendum, move G and rotate R will be constrained by your view (and by your pivot point for rotate) unless you explicitly constrain them to an axis or plane. The manual says that rotations are planar by default (as in they move geometry on two axes at once), but unless you specify an axis or plane, those operations default to the plane perpendicular to your view.

Here’s an example:
You are in Left Orthographic view (like in your screenshot). You can press G with those vertices selected and then press X to move them on the X axis. Once you start moving your mouse, the info bar at the top of the 3D viewport is going to tell you how far you are moving your vertices in a positive or negative direction on the X axis relative to the starting position. Click your mouse to accept, and you’re done.

Having the muscle memory to move geometry around in space precisely how you want really opens the door to making anything you like.