First, as always, a big thank you to everyone who has made Blender possible. No question Blender is one of the very best free and open source projects in the world.

To my surprise (again) this particular need of creating a 3D object from a 2D die line was not very well documented for Blender or out there in the internets.

Many thanks to the creator of this video even though it was so fast that I had to turn it down to .25 speed to make any form of sense of what he/she was doing! Hopefully this video plus my blog here will help someone suffer less.

Pre-Flight

1. Make sure that ‘import/export’ settings in preferences are turned on to be able to import images as planes
2. Make sure you have your die line as a .png image already created. I think it has to be png, but not 100 sure. You can use GIMP for doing things like this if you haven’t already discovered it.
3. In blender, delete default cube as usual
4. Set view to orthographic top (good habit)
5. OPTIONAL: create split screen with UV editor and modeling view visible at the same time. Use the checkerboard icon in the top corner to select UV editor view for one and 3D viewport in the other. This step may actually not be necessary if you aren’t tweaking the UV, so consider doing this step at the end if you need to further tweak the mapping.

Importing the Die Line Image as a Plane

1. Make sure you are in Object mode.
2. In the main blender top menu go to ‘file’
3. Go to Import > Import Images as Planes
4. Select your PNG file you created above and import it

• TIP: Don’t see your image on a plane? Grab your mouse and rotate a bit. It might have imported vertically and you may have to rotate it various ways so that it’s laying flat from orthographic top view. For me this was as simple as rotate (r) y (y-axis) 90 (degrees) (ry90) and then again 90 degrees on z-axis with rz90
• TIP: See it but it looks like a block of useless grey with no image on it? Likely you just need to change to rendered mode with z (menu) and 8 (rendered) mode.
• TIP: Something that messed me up for a long time when rendering (I had entirely transparent walls on my box!), is you may need to go into materials area of your plane, go to ‘blend mode’ and change to ‘opaque’. At least when you are rendering and find invisible walls!

Now you have your die line as an image on your screen

Loop cut and Edge Slide to Create ‘bend lines’

The package you are creating in 3D likely needs to bend so you have to put loop cuts on those lines to make sure you can bend them as you need later.

1. Tab into edit mode
2. Expose your left toolbar (blender 3.0 or slightly before has all these)
3. Mouse over the tools until you find the loop-cut tool.
4. Create a loop cut somewhere
5. Mouse over until you find the ‘edge slide’ tool in toolbar
6. Slide that loop cut until it matches the bend line in die line nicely
7. Repeat the above steps until all bend lines have a loop cut and that the loop cuts are nicely on the bend lines
8. Once all bend lines are created, go around the exterior of the die line with loop cuts and do the exterior of the whole thing and put loop-cuts around the perimeter, so you can cut out the excess garbage / plane material if any

Clean up the Easy Garbage

Now that you have the bends in place and perimeter marked out, remove the exterior garbage. You can see this done quite effectively in video above.

1. Use face select tool
2. Press ‘c’ to get circle select tool
3. Click and select every face you want to remove from the exterior of your die line
4. Press escape to get rid of circle select
5. Press delete key
6. Select ‘faces’ to delete the faces

Clean up the Difficult Garbage

Thanks to this guy’s video I was able to figure out a way to get rid of the angled garbage on some of my tabs by using the knife tool.

1. Go to face select mode
2. With the knife tool from the edit mode toolbar, bring the knife to the point on the edge until it highlights. (has to be on an edge to work it seems) and click your first point
3. Trace the curvature of your cut by laying down dots with the knife tool until the undesired surface area has been surrounded finishing by clicking the first point you created.
4. Hit enter key when ready. It may look like nothing happened,
5. Change to select mode from the knife tool mode using tool bar
6. Press ‘C’ to get your circle select tool and select the area you just created / cut (with the knife) tool. The surface of the undesired space should now be highlighted orange
7. Hit delete
8. Delete faces
9. Repeat until all the stuff on your die line with difficult angled areas are removed

Merge it

The creator of the video above ‘merged by distance’. I am still not exactly sure what this is but you can read more about it here if you’d like. I just quickly skimmed it and it seems it pulls all the vertices and edges together and makes it ‘one body’. I just obediently copied…

1. Edit mode
2. Select your whole mesh / plan / dieline with the A button until everything is selected
3. Go to ‘mesh’ menu
4. Merge > By distance
5. Choose .001m as per this video creator

I believe the quick test is to then select something in the 3D model view and grab it and see if it kind of pulls as one body pulling the other areas with it. Works for me…

Extrude it? Thicken it?

I felt the first round of doing this that my cardboard box was razor thin and not appropriate for corrugated cardboard. It would have been ok for cosmetic box perhaps as default, so I wanted to give it a bit of simulated thickness.

For me this was as simple as selecting all, and extruding on the z-axis to give it some thickness.

NOTE: this introduces extra challenges as it becomes much more difficult to select faces, vertices, etc, so you should consider your particular need. There is also the solidify feature but I found that applying this after it was already bent into shape did not work well at all. I’m just not sure the best way to deal with thickening the material…

Bend it

Now that you have your die line ready, you’re ready to bend some edges. A key tool here will be your ‘3D cursor’ – a real gem that I extracted from that turbo fast video above. It’s located in the top right menu of your 3D viewport screen and looks like a tilted number 8 with a dot in the middle or an attempt at an infinity symbol.. Go here and select 3D cursor which looks like a target sign or a cross-hair…

Before beginning, in your 3D viewport, drag your mouse around until you can comfortably see your die line and the angle you are about to bend.

1. Go to vertex select mode
2. Select a single vertex located on an edge that you would like to bend. TIP: You may wish to press z and 4 to move into wire frame mode to be able to more accurately select this vertex and then go back with z 8. Wire frame mode makes it much, much easier to select that one vertex on the edge.
3. Press shift and ‘s’ (shift + s) and choose ‘cursor to selected’ (option 2)
4. Change to face-select mode and make sure you are in 3d cursor mode
5. Before bending, observe your x,y,z and be sure which one you want to bend on
6. Select the face (or all the faces) you want to bend – TIP: If you extruded and added thickness before this phase you may need to use wire frame mode to be able to more easily select the original faces. And for this reason it may be better idea to do the extruding after the bending? You decide…) z8
7. r (rotate) x (example x axis) and a number (for degrees) or manually drag your mouse to move
8. Hit the Enter key to set it

TIP: If you do something like 90 degrees for all your bends, you will have faces overlapping each other in 3D space and it will look wrong. So consider bending more than that and compensate. You can also use the free-moving rotation with your mouse and do it by eye which works well. Shifting between wire frame mode and rendered mode is also very helpful (z4 / z8 buttons)

I hope some or all of this helped some or all of you.