The physical properties of objects can be changed with these buttons.
Press Escape to enter material combination mode. While in this mode, press the Shortcut Key of a material to add/remove that material from the combination. To exit this mode, simply press Escape again.
Alternatively, you can can open up the Attributes panel (Tools -> Attributes or Command + 7) to combine materials. (Mac Only)
Allows you to delete objects. (Shortcut Key: Z)
This liquid evaporates when it touches Heater. (Shortcut Key: Q)
This material does not move. (Shortcut Key: W)
This material does not change shape. (Shortcut Key: R)
This material expands and contracts. It can be attached to rigid objects. Heater melts it. (Shortcut Key: S)
This material changes shape when a force is applied to it. It attempts to go back to its original shape when the force is no longer applied. Heater melts it. (Shortcut Key: E)
This material changes shape when a force is applied to it. It shatters when a force that is stronger than a certain threshold is applied to it. Heater melts it. (Shortcut Key: B)
This rigid object rotates about its center of gravity. (Shortcut Key: X)
Like mochi, this material maintains its shape to a certain degree. It easily sticks to other objects. (Shortcut Key: M)
This material acts like rice. Upon impact, it breaks apart in a unique manner. (Shortcut Key: K)
This material explodes when it comes into contact with Fire or Heater. (Shortcut Key: P)
This material is not affected by gravity. (Shortcut Key: G)
This liquid resists flow. (Shortcut Key: V)
This liquid has high surface tension. (Shortcut Key: T)
This liquid is heavier than Water. (Shortcut Key: D)
This liquid is lighter than Water. (Shortcut Key: L)
This material ignites when it comes into contact with Fire or Heater. (Shortcut Key: F)
This material ignites Fuel, changes Water into Gas, melts Elastic and String, and makes Powder explode. (Shortcut Key: @)
This material ignites Fuel, changes Water into Gas, melts Elastic and String, and makes Powder explode. (Shortcut Key: H)
This material changes Gas into Water. (Shortcut Key: C)
This material gushes out Water. (Shortcut Key: I)
This material deletes objects that come into contact with it. (Shortcut Key: O)
This material accelerates objects that are attached to it. (Shortcut Key: J)
This material can be moved with the cursor keys. (Shortcut Key: U)