What are crossed volumes?

Crossed volumes are a common mistake making files not printable. To help you understand what crossed volumes in 3D modeling are, let us take a simple design. 

1. We’re going to use these two rectangle shapes.
2. If we decide to make them cross each other, we’re going to have this result.
3. That’s where things are going wrong: our two rectangles remain two separate entities, crossing each other but not being a unique volume: 
4. Unfortunately, a 3D printer has many difficulties reading these crossed volumes. The 3D printer could consider that there are three separate objects (the vertical rectangles above and below the horizontal rectangle and the horizontal rectangle) and, thus, will print them apart instead of a unified object.

Here is the solution to avoid crossed volumes: 

In the 3D software that you use, it usually is possible to unify the objects. Example with CAD software! You just have to click on the “Boolean Union” button that you can find in any CAD software, and your selected elements will be fused.

We have created several tutorial pages to help you create your 3D projects with different available software.

Below is an example of an object that was printed incorrectly due to the crossed volumes

From the 3D file, you may think that the below objects are unified:

When you use our online cutaway tool, you can see the crossed volumes:

The crossed volumes gave this printing result:

Please note if your object has crossed volumes, it is possible that the final proof request cannot be created.