A blog on software engineering by Trevor Brown

Blender Calculator

Here is a secret Blender feature. A calculator. No, there is no calculator window and no, I am not talking about the Interactive Python Console. This secret Blender feature can be found in every numeric input box and every slider button. Every input box can solve arithmetic problems just by entering in the equation and pressing enter. Simply click on the box and enter a problem like .8/3 and press enter.

This may seem like a worthless feature. A calculator? Why would I need that? If you have never used this feature it may seem pointless. However, this feature can dramatically speed up your workflow and once you have used this feature you won’t be able to live with out it! Here’s an example.

Say you are working with a material with a reflection value of .941 and you figure it is about one-tenth too reflective. Now you can guess a value. Somewhere ‘round .85, right? Or you can use the calculator. All you do is just left click on the slider, and then to the right of the number left click and enter the multiplication symbol * and then enter .9 and press enter. That’s it! You have now just lowered the reflection value by exactly 10%.


It can even solve algebraic equations like this: (I have no clue why you would need to do this.)

Algebra equation in inputbox

The Blender “calculator” will always round it’s answer to the nearest one-thousandth (unless your dealing with an integer value like the frame number, in which case it will be rounded to the nearest integer) and the results will not exceed the minimum and maximum values of the input box. Usually 1 is the maximum value and 0 is the minimum ( in some case there are no min’ and max’ values).

Hopefully, you can see the advantages to using mathematical operators in Blender’s “calculator” to perform quick, accurate changes to the value of a parameter. Once you get use to it, it will save a significant amount of time and greatly speed up your workflow. It eliminates the need of a calculator for complex problems.