Scale Objects

How do I Scale an Object to a Specific Size?

Scaling an Object Linearly

Scaling an object precisely is easy. If you want to scale all dimensions by a particular known factor, say half, select the object, and type S Key to scale it and press Enter Key. Type in the factor 0.5 into the Scale X field in the Resize panel, and press Enter Key. Then select the 0.5 value in the Scale X box and drag it down to the other two boxes below. Click in the viewport to finish. This “dragging down” can sometimes be tricky to master, but persevere. If you just can’t get it right, then type 0.5 into the Scale Y field and the Scale Z field for the moment, and try again next time.

First type in the factor in the Scale X box, select the it and drag it down

Scaling an object – Unevenly

It gets a little more complicated to scale the width, length and depth to different precise lengths.

We use the Measure mode Measure Icon together with Ctrl Key to snap to the corners. Click here to read the article on Measuring.

Object with dimensions
Object with dimensions for Length, Width and Height

Now let’s say we want:

  • our length to be 4.5m instead of 4.32986m,
  • our height to be 2.5m instead of 2.55694m and
  • the depth to be 1.75m instead of 2m

We use simple proportion that we all learned at school, but we let Blender do the Math. We can scale in all three global axes. Let’s take a look at this object which is aligned orthogonally to all three axes:

To scale the object we click the Select Box mode Box Select Mode , select the object, and type S Key to scale it and press Enter Key

Ignore the values in the Resize parameter panel, replace them with:

  • 1/4.32986*4.5 for the X Scale (simple proportion)
  • 1/2*1.75 for the Y Scale
  • 1/2.55694*2.5 for the Z Scale:
Scale Panel
The scale panel with the first two fractions already entered and the final one about to be entered.

We now return to Measure mode Measure Icon to check whether we didn’t have any “finger-trouble”:

Delete the old dimensions

Apply the scale Ctrl KeyA Key

Now re-dimension the object:

The dimensions are correct.

If you are scaling when the object sides are not aligned orthogonally with the Global axes, then you need to change the orientation in the resize parameters panel to Local:

Resize Orientation
When the object is rotated, change the Orientation to Local

The Bounding Box

Once you have an object ready to Scale to a specific size,it is useful to display the object’s bounding box. Select the object and click the Object Properties tab Object Properties Tab of the Properties Editor panel. Expand Viewport Display and click the checkbox Bounds :

Click the checkbox to make the Bounding Box visible

A Bounding Box is defined as the smallest rectangular box the object can fit in. All internal angles are 90 degrees.

  • The Bounding Box visually confirms what sides of the object are aligned with the global axes. Like a cross-check.
  • It also gives us the ability to scale the object’s X, Y and Z components when it is not parallel to the axes, and that object must nevertheless fit into a specific volume.

What is a Bounding Box in Blender? – ScruffyFluffy 3D Learning

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