ProCutter and Reactor

In this tutorial we are going to take a look at a method of breaking things into smaller pieces using the Compound object ProCutter, and then animating them breaking apart with reactor physics as I am still using 3DS 2010. Mass FX works similarly though, so the idea can be carried forward in the later versions of Max, and we'll do a few tutorials for them as well in the near future.

Just so we aren't starting with something boring like a sphere or anything, I have made a quick Lathe model of a vase which I am going to use in this tutorial. You are welcome to either model something you want to break yourself, or download the starter file here:

http://animation.diclementi.com/tutorials/fracture_start.max

Upon opening the file you should see this simple model of a vase, the first thing we are going to do is make a copy of it, so that we have one to destroy, and one to keep nice and whole.

So, right click on the vase to bring up your Quad menu, and select Clone from the menu.

--->

Select Copy in the menu, and give it a new name.

Then select the first vase (I believe it is just named Line01) and right click to bring up the quad and then just Hide Selection for the time being, so that the only vase left in the viewport is the one we intend to break apart.

Next, we are going to create a plane which we will use to cut the vase into pieces.

I am going to draw my plane in the front view to start, and make sure it goes all the way through the vase.

As the plane will be used as a blade of sorts to cut the vase into pieces, I am going to add a few segments and then we'll adjust it as an edit poly to give it more jagged or serrated edge.

I gave my plane 8 width segments and only 1 length so things don't get too crazy.

Next I will right click on my plane to bring up the Quad and convert it to an editable poly so we can adjust the sub-objects of our blade.

Then, on your modify tab, turn on the Vertex sub-object selection mode.

Then in your top view, drag a selection around every other vertex on our plane. Use your rectangular marquee selection so you get both the vertices at the top and bottom of our plane.

Then simply move the vertices down in the viewport to create a sort of jagged saw pattern to our blade.

Then turn off vertex sub-object selection and move your plane into place so it cuts directly through the vase.When you have the first blade where you like, hold down shift on your keyboard to use the clone shortcut and using your rotate tool, create multiple blades and position them so they cut through the vase in various locations.

Do this several times so that we have these blades dissecting our vase into many smaller pieces.

End result should look something like this, with several blades chopping this thing into many sections.

Now with one of these blades selected, go to the create tab, geometry, and in the dropdown menu find Compound Objects. In this menu you will find the ProCutter tool.

Click on the ProCutter button with only one of your blades selected in the viewport and make your settings match mine below:

Mark all the checkboxes that you see to the left here.

Then click on the button at the top that says "Pick Cutter Objects"

With this toggled on you can now select all the other planes we created for our blades one by one until you have them all.

They will show up white and selected when you have added the blades to the selection, as well as they appear in the list below our settings in Cutter Parameters now.

Next, click on the button that says "Pick Stock Objects"

Then click on the "BrokenPieces" copy of our vase.

Give it a moment to calculate, and you should see your once all yellow colored vase is now in many multi colored pieces.

Now we can simply delete the blades by hitting the delete button on your keyboard.

It will have turned your original vase copy into many editable meshes. I like to change these to Edit Poly because it is just a bit of a better way to adjust the pieces and clean them up.

Select all the pieces, right click to bring up the quad, and select Convert to Editable Poly again.

You should notice that some of our pieces are a bit misshapen, this is due to 3DS Max trying to smooth things out automatically and may require us to go into each piece and edit the smoothing groups for a cleaner broken piece.

Select one of your pieces, and turn on your Element sub-object selection mode. Then select the element in your broken piece of vase.

Down in the Edit Poly settings, find the rollout menu for Polygon Smoothing groups, and then simply click on the Autosmooth button which should be defaulted to 45.

Clicking on the Autosmooth button should redefine the smoothing group to a 45 degree angle for all the polygons and should do a pretty darn good job of getting rid of those unsightly edges and corners.

Then just turn off your Element sub-object selection mode, and do this for each piece in your broken vase until it all looks smoother, just like the one piece we just did:

I have taken the time to smooth out all my pieces (tedious but necessary for a good result in our animation) and now we can continue!

It isn't perfect but for our purposes, it will do just fine and it does look 100% better than the original pieces.

Now we can create and give these pieces a texture instead of leaving them rainbow colored. You can create a texture yourself later, for now I am just going to apply one of the default grey textures to it in order to unify our pieces.

That does it for the cutting our vase into pieces portion of the tutorial, now let's do a bit of reactor physics simulation using Rigid Body collections, and Fracture.

Select all your pieces and move them up along the Z-axis to a height that we can drop this thing from.

I have selected all my pieces and with my move tool selected just typed in 400 in the Z-axis location settings.

With all my pieces still selected I am going to create a Rigid Body collection from my reactor panel.

If you don't see your reactor panel, then just right click in the empty space next to the buttons at the top of your screen and enable reactor.

This will pop up the reactor panel buttons, either at the side of your screen or in a floating window.

With all the pieces of your vase selected, click on the Create Rigid Body collection button, which looks like 3 stacked boxes in the reactor panel.

This will add them all to a Rigid Body Collection and will create an icon for you.

When you select the icon and go to your modify tab you can see that all the pieces have indeed been added in the list as well as add anything else we need to here.

We are going to have to add something to stand in for the ground in this simulation, so we can make a Reactor Plane.

turn the reactor plane toggle button on, and then click in your viewport to create the plane.

A reactor plane is an imaginary surface that extends indefinately in all directions to simulate the ground.

Select your Rigid Body Collection Icon, and on the modify panel, add in the Reactor plane to the Rigid Body Collection.

Click the Add button, and find the Reactor Plane in the list to add it to the collection and the simulation.

Then select all of your vase pieces again, and go to your utilities tab (looks like a little hammer in the command panel to the right)

Make sure you only have the pieces of your vase selected and not the Rigid Body Collection or the Reactor Plane.

Utilities Tab

Click on Reactor button to open up the settings.

Open the properties rollout menu and double check that you have just the pieces of the vase selected, all of them.

Then give the pieces a mass of 25.0

and check to make sure they are marked as Mesh Convex Hull.

Then open up the Preview & Animation rollout, check the box that says "Update Viewports" and then click Create Animation.

Say OK to the dialogue box that pops up asking if you are sure you want to do this.

Then let the animation calculate in front of you, it may take a minute or two.

When it is finished you should have a nice simulation of the broken vase falling out of the sky and colliding with the reactor plane and breaking into pieces.

It looks great, but we aren't quite done yet. We need to make this vase look as though it breaks only when it hits the ground, so we have some tricky illusions to pull off still.

As I scrub down my timeline I see that the vase hits the ground at about frame 39. So with all my vase pieces selected, I am going to select and delete all the frames that come before frame 39.

drag a selection box around the frames 0 through 38, they should show up white when selected, and then hit Delete on your keyboard to get rid of them.

This leaves us with just the frames where the broken pieces fall apart, and a nice blank space to play with the visibility of our vase before that.

With all the pieces still selected of the broken vase, turn on AutoKey,

then move your scrubber to frame 38,

and then right click the pieces in your viewport and find Object Properties in the Quad.

Change the Visibility to 0.0. A little red bracket around the up and down arrows will appear letting you know that you have just animated the numbers to hit 0 visibility at the current frame.

Then hit ok, you will then see 2 new keyframes on your timeline created for you. One of them at frame 0, and the other at frame 38.

At frame 0 the pieces of the vase are fully visible, and at frame 38 they are now invisible. We want to make our pieces invisible until frame 38, and then have them become visible at frame 39.

So all we have to do is select the keyframe at 0. and move it over to frame 39.

Then turn off Autokey. This should make your broken pieces invisible until frame 39, and then they will show up and smash instantly.

Now, remember that original vase we kept and hid from view at the very beginning of our tutorial? Right click anywhere in your viewport and from the Quad menu select Unhide All.

Your nice whole vase with no smashed pieces should re-appear.

We now need to animate this vase falling between frame 0 and 38. So it looks nice and unscratched just before impact.

Lets select our vase without broken pieces, and move it up to the same height we dropped our pieces from.

Now select your Rigid Body Collection icon.

On the modify tab, in the RB Collection Properties, select all the pieces of our vase in the Rigid Bodies list, and hit the delete button to remove them from the simulation (they are done, and we don't want to re-simulate them)

The only thing left in the list should be the Reactor Plane we used as our ground. --->

Then click on the Add button, and thistime add the whole unbroken vase.

Now, turn on your autokey again.

and select your intact vase.

Move the scrubber to frame 39, and right click on the vase and go to Object Properties.

At frame 39, make the vase completely invisible just like we did with the other pieces, and hit OK.

Then when you see your two new keyframes at 0 and 39 for the intact vase, simply move the one at 0 to frame 38. So the whole vase stays visible until frame 39 and it will vanish as the broken vase appears.

Then turn off your autokey again.

With your intact vase selected go to your utilities tab and open the reactor settings again. Find Properties and give the vase a weight of 25 just like we did with our pieces.

Then up in the Preview and Animation panel, hit the Create Animation button. -->

You can delete any of the keyframes that the simulation makes for you after frame 40.

now you should see the fully intact vase falling from frame 0 to 39, and then the broken pieces falling apart from frame 39 to 100. Now that the simulations are finished you can delete the reactor Rigid Body collection icon and the reactor plane from the scene, add a real plane to your scene so we can see the actual ground.

Then simply assign the same texture to both the fully intact and the broken pieces of the vase and you are ready and set to light the scene and render.

You can view a full rendered movie of our final animation here:http://animation.diclementi.com/brokenvase.html