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Tutorial: Modeling and Animating Movable Box Flaps

21

MonsterWebMonsterStudios, a partner with MonsterWeb (the unlimited web hosting people), has recently published an animated commercial (completed entirely with Blender) for use on the MonsterWeb site (it's on the main page).

After MonsterStudios was done and we got a look at it, I was interested with what method he used to do the box flap animation. MonsterStudios was more than happy to share it's secrets with the Blender Community, so Daniel LaBarge, a MonsterWeb employee, gave a quick tutorial on how the box animation was done.

*Edit: After some comments I added more to the tutorial to (hopefully) make it more clear. I would also like to warn everyone that this is not a "beginner tutorial" since it goes over major concepts rather quickly. But if you have a question - post it!

**Edit: I just did this as a video tutorial (22.4 MB XviD, remember to right click and Save As!), in case someone was having trouble.

Creating an Animated Box

Step 1: The first step to creating an animated box is adding a cube (Spacebar > Add > Mesh > Cube). After you create the mesh, you wil be in Edit mode. As you see in the below top image you will need to be in "face select mode" which you can enter by clicking the hollow triangle on the far right of the toolbar (or by using Ctrl + Tab > Faces). Select the top face and hit the X Key to delete it. You should then have a cube with the top missing as seen in the below bottom image.

box3.png
box4.png

Step 2: Go to the top view by hitting the 7 Key on the number pad. Enter Edge Edit Mode (Ctrl+Tab > Edges). Then select each of the top four edges (as seen being done in the top image below - here I am in the middle of extruding the bottom flap) and extrude them along the horizon out approximately half the width of the box (1.0 units). You can get straight flaps by holding down the Ctrl Key to snap to the grid. You should now have a hollow box with four flaps (in the image below bottom I have left the top view to show you what you should end up with.

box61.png

box81.png

Step 2a (Optional): If you would like to go a little futher, you can add depth to the paper thin box select the faces of the box flaps and scale them a very small amount (the box in the MonsterWeb has depth added throughout the box, but the just doing the flaps will be fine for now). Next we need to add an armature.

Step 3: In top view (7 Key on the number pad) add an armature at the center of the box along the flap horizon (Spacebar > Add > Armature).

box12.png

Create a bone for each flap by placing the root of the bone at the bottom of the flap near the middle of the flap and the top of the bone at the top of the flap near the middle of the flap. Once the armature is created and a bone appears, it and each subsequent bone you create from Add > Bone (see the image below), you will need to selct the bone and move it into position. Using the Ctrl Key to snap to the grip really helps in placing these. Be sure to keep the center of the armature in the same place while moving the bones around (which shouldn't be a problem if all you select is the bones. Give each bone an unique name so that it's easy to identify when adding vertex groups.

box6.png

Step 4: After adding the four bones in top view, leave the top view and check your work. You'll notice that the armature (all the bones) are not on the flaps but below them. To get them aligned you will need to move the armature up to the flaps. To ensure I get the whole armature and not just one or two of the bones, I selected the armature in the Outliner window. To get an Outliner window split the viewport and switch one of the windows to the Outliner view. When in the Outliner view go to View > Show Outliner. This is seen in the image below:

box10.png

I then used the Grab widget (Ctrl + Alt + G Key) and used the arrows to grab the armature and move it up to the box flaps (again using the Ctrl Key to sanp to the grid). See below for the final result:

box11.png

I also like switching to Stick armatures for this kind of a rig. You can change how the bones look by going to the Armature box when you selct the armature or bone in edit mode (see below for the Armature box with the "stick" view selected).

box15.png

Step 5: Next step is to parent the box to the armature without applying vertex groups (Select the box > select the armature > then Ctrl+P Key > Armature > Don't create groups).

Now select the box and enter edit mode. Select each outer vertices of each flap and in the Edit Buttons (F9) create a new Vertex Group (where the word "Group" is highlighted in the image below) called the same name as the bone that the flap edge corresponds to. Then with those vertices selected, click Assign to tell Blender to assign the vertex group to the bone (for example the vertex group "top" with the bone named "top").

box8.png

Step 6: Exit edit mode and select the armature and enter pose mode (Ctrl+Tab). Select a bone and rotate it. If all goes right you should now have the outer edge parented to a single bone and when the bone rotates, the flap should open and close. Ctrl + Z Key to undo the test rotation you just did.

Step 7: In order to animate the box flaps you will need to first split the window and open an IPO view (see the image below). Make each window use the "Pose mode" which you can see in the image below with a yellow circle next to the name. I like using the rotation widget (Ctrl + Alt + R Key) for this kind of rotation because it offers more control.

So with a bone selected, use the widget to control the rotation in a single direction in the position at each frame you want it (I use the IPO window to slide to the frame I want to use). When you have selected the frame you like, in the 3D view window that shows the bone and box hit the I Key and insert a Rotation key (as demonstrated in the below image). This will ad the key to the IPO window at the desired frame. It will also add keys for rotation directions you do not use (they will look like horizontal lines in the IPO window). In the example image below I removed the other rotation keys we do not need.

Some animating tips: When using the IPO window to manipulate keys, most of the commands are the same you will find in the main 3D window (e.g. G Key for grab, A Key to select all the keys, right click to selct, etc). To make it realistic open each flap slightly after each other with the bottom flaps opening last. Also box flaps don't usually open linearly so give them a sudden spring and then a recoil and bounce as they fall to the sides!

box14.png

Download the Box Tutorial .blend File

Confused by all the key strokes? Worried you won't remember them? Then the Hotkey map is something you shouldn't be without.

MonsterWeb and MonsterStudios would like to take the opportunity to say thank you to the Blender Community and the Blender Foundation for creating such an amazing software and for offering it to the world for FREE!

About Author

Eugene

Just a guy really into 3D, especially where Blender is concerned.

21 Comments

  1. I was thinking about this today, as I was researching some info on Yafray in BlenderArtists...

    There was an excellent article regarding Yafray, but it was solely done in Czech (no offense to any .cz members out there - from the little I've seen, the Czech community is truly doing some really amazing work! And, btw, I was able to follow along with the detailed screenshots - so I really don't understand all the hubbub). Well, the thread turned to the whole issue of translating the pages - and eventually, someone mentioned paying someone to do it (apparently, translating from Czech to English or something is much more work than one would think...).

    The really cool response was along the lines of, "since we are taking so much from the open source community (i.e., Blender, Yafray, Gimp, etc...), why should we worry about being paid? It's an opportunity to "give back" to the community. Some do it with tutorials (which, btw, I think a lot of us would be back to the pulling-out-hair stage if there weren't as many great tuts out there.), some do it by challenging the rest of us with great Blender work, some do it by producing a short-film (thereby displaying that Blender can compete with the so-called 'big-boys'), some do it by giving assistance in the forums, etc., etc., etc...

    I think it's great that there are people out there in the world - in the marketplace - utilizing Blender in real-world applications. And it's really great when they are willing, and eager, to share their experiences.

    Just a thought...

  2. Nice tutorial, but there are some confusing points for newbies at the very beginning.

    The following details may help:

    1.) Make sure you're working from the Top view by pressing 7 on the keyboard's numpad.

    2.) You are already in Edit mode after creating a mesh so, pressing the Tab key puts you in Object mode. Don't press the Tab key after creating the cube.

    3.) To delete the top face of the cube, press Ctrl-Tab to bring up the editng Select Mode menu. Select Faces. Now you can easily select the top face.

    4.) When creating the flaps, extrude each edge separately. Select an edge and press E. Hold the Ctrl-key down while extruding the edge so it snaps to the underlying grid. Extrude each edge one grid unit. The sides need to be extruded horizontally. The top and bottom edges need to be extruded vertically.

    That's the basic box.

  3. I dont have a clue what to do this is the worst tutorial ever.....................
    So now blender is something i'm NOT going to put on my wish list.....................
    It's RUBBISH!!!!!!!!!!!!!!!!!!!!

  4. The Cheese mister on

    Can someone make an easier tutorial this is the most complicated thing ever, i don't have a clue what to do... My friend didn't know what to do either! I've tried many times and still dont know what to do. And...... Who ever wrote the bob thing i think you are over reacting..

  5. It's not a bad tutorial, but it is not a modeling and animating tutorial. It assumes you know how to model and animate (and there's some good tutorials out there about how to do that), and focuses on the particular technique for moving the flaps of a cardboard box. Eugene (etr9j) probably should have warned everyone that this is an intermediate to advanced tutorial, and mentioned what skills you'd need that "go without saying" in the tutorial, such as working with vertex groups and armatures, using the IPO window, rendering an animation... Kind of ironic the article before this one is "Completely lost in Blender"

  6. Eugene is not to blame for this tutorial. The original tutorial that I wrote was even more advanced, he actually dumbed it down for me. I've taken time to rewrite the tutorial from a beginner to intermediate level view. It still doesn't discuss what is happening - simply what to do to achieve the results. There are plenty of great tutorials out there for you to follow up on, on what really went on. I've resubmitted it to BlenderNation so expect an update soon.

    Daniel

  7. Eugene (etr9j) on

    Based on everyones comments I have written more to the tutorial and added some images.

    @bob and The Cheese mister
    Tell me if this is more clear.

    @Willie
    Good call on the warning and the amusing statement about what post was before this one :)

  8. Please edit the very first sentence in the tutorial. It is wrong. After creating a mesh, you will already be in Edit mode. Pressing the Tab key, as suggested, will put the User into the Object mode and beginners will be lost from that point onward.

  9. Good work, Eugene. Wow, that was fast! For the newbies, I'd just like to hammer home a couple of important points about vertex groups, which are the key to making this style of animation work.

    First: the vertex group MUST have the SAME NAME as the Bone that moves it. So, decide what names to use (I used NorthFlap, SouthFlap, EastFlap and WestFlap) and give the name first to the bone, then, when you make a new vertex group, give the name to the vertex group. Spaces, caps, underscores, everything is significant. The names must be exactly the same or moving the bone won't move the mesh!

    Second, the vertices you want that bone to move must be assigned to the vertex group (and ONLY the vertices you want moved, I might add.) So make sure first that nothing is selected in the 3d View window, then use the Bkey to select just the vertices you want to move (make sure you have them all) and press the assign button on the vertex group side of the links and materials tab (the small assign button - the big assign button on the other side of the tab is for materials). TA DA! you've done it.

    Unfortunately, Blender gives no indication that anything has happened. To check your work (and we all like to check to see if what we did had an effect) deselect everything with Akey, then press the select button that's right under the assign button. The vertices should light up for you, showing they are part of that vertex group.

    Finally, the remove button takes selected vertices out of the group, the deselect button deselects all the vertices in the group that were selected, and the delete button gets rid of the entire vertex group, so if your group inadvertantly gets some extra vertices, use these buttons to fix it.

  10. @Kernon
    Thanks for the correction! Fixed!

    @Willie
    :) The speed came from my motivation to make the tutorial as useful as possible. Thanks for the additional comments/clarifications!

  11. This technique is also usefull for all these things that require mechanical simulation and rotation of some vertices from a mesh where you can't use shapes. So are doors, hinges, ....

  12. etr9j, Your welcome. Its like footnotes. If you put it in the body of the tutorial, it just gets in the way and makes things booring for the pros and confusing for the newbies. If its not there at all, someone working through the tut can miss a vital point (five or six words in the middle of a long paragraph) and get stuck. I like Colin Listers (sp?) tutorials: he spells out which skills you need to do the tut in the first paragraph. I'm really looking forward to the Summer Of Documentation projects, not only for the new information, but also to see models of really good documentation.

  13. Off topic a bit ...
    Some of the sample webpages are about companies in New Braunfuls TX. I live in Schertz TX. It would be cool to meet some local people using Blender. Send me an email if you have the time.
    -Greg

  14. Eugene (etr9j) on

    For posterity, I did this as a video tutorial in case some beginners that want to give it a shot were having trouble. You can find the link in the **Edit in the post.

  15. Wouw, my first thing made with blender is rendering. Didn't thougt I could do this with only one hour of blender experience (after this it isn't only 1 hour any more). Thanks for the tutorials.

  16. Hi Eugene, just wondering...
    In the beginning of your video tut, you show how to enable the view names. However, I don't have this option there? The tutorial shows you're using 241, so do I..

  17. @mattie
    I know I answered you about this in the Multiple materials tutorial thread, but I thought I would but this for the record here for everyone that might have the question.

    I was using a cvs build (a pre-2.42 release), which has the option for "View Names."

  18. Wolfgang Benfattoum on

    I just made a 10 second animation a few days back, where I made a die unroll its face, using only keyframes (IPO's). I had a few problems initially but managed to compromise with six individual faces parented to an empty. If somebody is intersted in discussing this any further, let me know.

    Ben der Render

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