How to Merge Objects in Blender

Want to combine multiple objects into one in Blender? Here's how to do just that.

When modeling in Blender, sometimes you want to join or merge objects together as it makes the modeling process easier. In this article, we'll look at how you can merge objects in Blender. We'll start by learning how to join, then add and subtract two objects from each other, and finally on how to join objects in Blender 2.90 by applying modifiers.

Joining Objects

For those who don't know, Blender is a free and open-source 3D graphics software tool, and was downloaded over 14 million times in 2020. Although it has a steep learning curve, it definitely helps to break everything down into steps. When you're just getting started with Blender, one of the fundamental tasks you will need to learn is on joining two objects together.

To start off, it doesn't work the way a lot of people may expect. When the objects are joined together, they are actually not geometrically connected but are simply marked as one object. While you can rotate, scale, or move them, they do remain unattached.

For example, you could be modeling a complex miniature model, or a mechanical part that must be assembled after printing. So for clarity's sake, you can join the pieces together in their assembled state while in Blender, then have them printed separately in actuality.

However, before we dive into the steps involved in joining objects, here are a few things to understand:

• The parent: There is always one object that will be the "parent" of all other objects that are being joined. This could be the most prominent object, the body of a character model, for example. To select an object as the parent, it will need to be selected last.
• Other parts: It's key to remember that even if the objects are touching when being joined, they are not connected together. They are simply intersecting through one another. However, by doing so, it is easier to check for errors. For instance, it is not recommended to print where there are intersecting areas between objects in a model. That said, again, they will act as one object and will rotate or scale together.

Without further ado, here are the steps to join two objects:

1. Select the first object by left-clicking on it. This would be the non-parent object.
2. Once selected, hold down the Shift button and then left-click on the other object. This last object is the parent object. You may also realize that one object is highlighted yellow (or arguably a lighter orange) and the other in orange. The object that is highlighted in a lighter orange or yellow is the "active object" which indicates the last selected object.
3. Now with every object selected, click on the object menu, or press Ctrl + J.
4. Click on the Join button found in the object menu.

After these steps, the objects will now act as one.

But what if you really want the objects to be attached together? Read on.

Adding Objects

As mentioned above, joining two objects does not actually attach them together as they still exist as separate geometries. To actually attach them together, we can do so by simply using modifiers. That said, this approach will only work with two objects. However, it can be repeated to attach more than two objects together.

You simply repeat the step for each extra object till you have one complete model. With all that said, you will need to select one particular object as the one that the modifier will be applied to. For simplicity's sake, we'll call this the main object.

Here are the steps involved in adding one object to another:

1. Left-click on your parent object. In this example, we're using the cube as the main object. Now with only this object selected, locate the properties editor. This is found on the right side of the screen under the outliner. Select the modifiers tab which has a wrench icon displayed.
2. Click on the Add Modifier button, and you will now see a list of available modifiers.
3. Select a modifier by left-clicking on it. In this particular case, we are looking for the Boolean modifier.
4. Once selected, you will see the modifier displayed. In this state, it has yet to be applied. First, you will need to know the name of the object you want to attach to this object. Click on the blank button next to the section marked Object, and you will see a list of objects appear.
5. Select the object you want to attach to this main object.
6. Tinker around with the Operation section in this modifier. There are three options here: Intersect, Union, and Difference. In this case, we select Union.
7. They are now ready to be attached together. To do so, click on the drop-down arrow icon and click Apply or simply press Ctrl + A.

Subtracting Objects

There are times when you need to cut out an object from another object. For example, to engrave text or a particular shape into another object. To do so, once again, we can use the Boolean modifier but this time with different settings.

Follow the steps below to do that:

1. Repeat the first two steps in the previous section. Remember that the first object you select should be the object that you're cutting into the other object.
2. In the Boolean modifier settings, select the Difference operation.
3. Now select the other object by clicking on the empty box next to Object text. Find your other object listed there. In this case, we want to select the cube.
4. Finish the process by applying the modifier with Ctrl + A.

Final Tips on Applying Modifiers

Finally, we have a few tips for you to remember when applying modifiers to your objects. It may not seem obvious at first glance, but to see the subtraction of your object, you might want to delete the subtracting object. Select it, then press Delete on your keyboard to see the final results.

Can't select the second object without selecting the subtracting object? Use the outliner found in the top right corner of the Blender screen in the default view. Click on the second object, then move your cursor into the 3D editor. Press the Delete key.

And well done. You've learned how to merge objects in three different ways, enabling you to do a lot more with your models in Blender.

About The Author