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[Tutorial] Blender – Unit Systems for beginners & How to use them

Yes, you can use real world units in Blender. And I feel ashamed, but when I was a Blender beginner, I didn’t know this for years! When I started working with architecture, and discovered the unit systems, that was a major game changer for me. With the units, you can keep the real objects proportions, suit exports from other software into your .blend scenes or use them for the precise 3d printng. In this article, I will introduce you to the unit systems in Blender and show you how to use them with your work.

Setting up the units for your scene

By default, when you install Blender for the first time, it uses it’s own numerical units. You may stop at this point and use Blender units for your work, if you don’t need anything more. But in my opinion, using the real world units is much much better for your projects, as it is much easier to imagine or measure. For me using meters, centimeters, milimeters is just much more intuitive, than using 1.0, 0.1, 0.01, 0.0001, especially when working with real objects or projects.

To setup your unit system, simply go to the Scene Properties tab in the properties workspace. It should look like below:

There you should find the section called ‘Units’. The very first property there is our Unit System. By default, None will be set, and you can change it to Metric or Imperial, depending on what you want to use. As I live in Europe, in my case it’s Metric.

Below, you can change the default Units of measurement. The values there will mean what unit will be used for representing the operations you make in Blender, like moving, rotating etc. Also, this unit will be used when you will be typing the transformation values by hand. When working with architecture-scale objects, it’s the best for me to use centimeters as default, I usually leave the other values unchanged.

If you don’t want to set up the units each time, simply set this up in the new blender instance, and save it as the startup file

Units practically

What many users are asking about, is how to see the units in the viewport. This is really simple, and it does not require any external addons! To enable measurements in the viewport, open the Edit Mode and go to the Viewport Overlays. There you should find the section called Measurement.

There are four types of values, that you are able to see in the viewport – Edge Length, Edge Angle, Face Area and Face Angle. I mostly work only with Edge length, but the setting is up to you and your needs.

Enabling those options will allow you to see the dimensions of the selected or edited elements of your mesh. So to see faces edge lengths, select the desired face. And all the values here will be shown with the measurement unit you’ve set up it the scene’s properties. If the things get too messy or you simply don’t need to see the measurements, simply open the viewport overlays again and disable the settings.

Let’s now use our units for some transforms, as this is basically the most frequent operation. Add a cube, go to Edit Mode and select one face. Click G to start the translate operator and optionally make this transform along the perpendicular axis. On the topbar you should see dynamically changed value, that shows you what is the value of your transform. And again, in this case you should see this value represented by the unit set up in scene properties.

Now, type some value by hand. Let’s say I want to move my face by 100cm. So if my unit is Centimeters, I simply type 100.

If I set up my length unit as Meters, I’d need to type 1 instead of 100, to have the same result. So this is why setting the measurement unit is so important – it helps a lot to keep the work simplier, but it always should be fitted to the scale of the project. So for example I’d use meters to work with city-scale project. For regular archviz I always use centimeters as it is the most precise and comfortable unit for this scale. If I’d work with some micro elements, I’d surely used milimeters or micrometers, while using them for larger objects would be just annoying. (To move something by 5 meters, I’d need to type 5000 milimeters etc.)

The units are also used when you are adding new objects via Shift+A. When you add any default object, the small popup shows up in the lower left corner. And there are plenty of unit-based settings like size, location or rotation. And usually size is the most important and most used among them.

In this case you can not only type the numerical value, but you can end it with the measurement unit. So to create 100 meters large cube, you don’t need to type 10000, but you can type 100m for the same result.

This one is also useful, if you want to create the object based on another Unit System, like Imperial, because you can type here the unit from this other system. For example, you are working in Metric system, but you want to create some TV screen, which size is based on inches – simply crete the plane with the size in inches. Blender will automatically convert this value to your unit system

Why it’s a good practice to use units?

In my opinion, using the units is very good practice, it’s even crucial if you work with interior or architecture visualizations or 3d printing. Mainly, it’s the only way to keep the right proportions and size of your objects. Also, many assets from external websites like 3D Warehouse, when exported are using real units. Sometimes it happens, that this kind of objects are overscaled, but it’s usually enough to scale them with the multiplication of 0.1 or 0.01.

Also the objects from our libraries – Interior Essentials and Architecture Elements are created using the real-world units. So if you keep your scene with the right proportions and add any assets from one of those libraries – they will always be suited right, without the need of scaling them each time to suit the scale to the scene.

I hope this short article showed you the basics of the units systems. Of course, this is just a basic knowledge, and there is much more with the units, like in physics operations, animations etc, but I believe that with this basic knowledge, you should be able to discover more yourself and suit it to your own needs!

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I'm the founder of digital.ARCH and all our products. I work with Blender since about 2008, and this time help me to gather a lot of experience with this software