Each element in TPT has properties associated with it that apply to all particles of that type on the screen. This is a list of all those properties (for use in both C++ and Lua)

Properties

Identifier	Identifier string, used for lua and internal stuff. Formatted like DEFAULT_PT_XXXX.
Name	Name, it is recommended to use 4 letters or less. 5 or more will probably not fit on the buttons. (SPWN2 previously showed as "S..." but now the name just overflows outside of the button)
Color	Default color, in hexadecimal (RRGGBB). In the deco editor, it will tell you the color in hex, ignore the initial FF, and use the 6 digits after for this. The initial FF is the alpha or transparency part of 32-bit color.
MenuVisible	If it's visible in the menu, if 0 then it is hidden. By default is 0.
MenuSection	The menu section it's in. See below for a list of possible values.
Enabled	If 0, it cannot be created or seen in any way, not even lua. It will just disappear if somehow created. Used for removed elements, you should leave this 1.
Advection	How much the particle is accelerated by moving air. Normally 0 for solids, and up to 1 for other elements. It can be negative, and do this so they go towards pressure.
AirDrag	How much air the particle generates in the direction of travel. Generally is very small, 0.04f creates a lot of positive air (- creates negative pressure)..
AirLoss	How much the particle slows down moving air (although not as big an effect as a wall). 1 = no effect, 0 = maximum effect. Solids are generally above 0.90f, along with most other elements too.
Loss	How much velocity the particle loses each frame. 1 = no loss, .5 = half loss. Solids have it at 0. Only a few have it at 1, like energy particles, and old moving sponge.
Collision	Velocity is multiplied by this when the particle collides with something. Energy particles have it at -0.99f, everything else is -0.01f or 0.0f. This property does not do much at all.
Gravity	How fast the particle falls. A negative number means it floats. Generally very small, most gasses are negative, everything else is usually less than 0.04f.
Diffusion	How much the particle "wiggles" around (think or ). Set at 0, except for gasses, which is a positive number. Up to 3 (or higher) for a large amount of wiggle, GAS is 0.75f, HYGN is 3.00f.
HotAir	How much the particle increases the pressure by. Mostly used by gasses, but / have theirs at (-)0.010f, and certain cold/hot materials (e.g. ) have a slight negative value. Usually it's an extremely small number, sometimes as small as 0.000001f.
Falldown	How does the particle move? 0 = solid, gas, or energy particle, 1 = powder, 2 = liquid.
Flammable	Does it burn? 0 = no, higher numbers = higher "burnage". Something like 20 is WOOD, while C-4 is 1000. Some are a few thousand for almost instant burning.
Explosive	Does it explode? 0 = no, 1 = when touching fire, 2 = when touching fire or when pressure > 2.5. Yes, those are the only options, see FIRE.cpp or somewhere in Simulation.cpp to modify how they work. You MUST set the Flammable property also for this to have any effect.
Meltable	Does it melt? 1 or higher = yes, 0 = no. This is actually only used when heat sim is off, to make it actually melt use element transitions.
Hardness	How much does acid affect it? 0 = no effect, higher numbers = higher effect. Generally goes up to about 50.
Weight	Heavier elements sink beneath lighter ones. 1 = Gas. 2 = Light, 98 = Heavy (liquids 0-49, powder 50-99). 100 = Solid. -1 is energy (, etc).
Temperature	What temperature does it have when spawned? Temperature is in Kelvin (Kelvin = degrees C + 273.15). R_TEMP+273.15f gives room temperature.
HeatConduct	0 - no heat transfer, 255 - maximum heat transfer speed.
Description	A short one-two sentence description of the element, shown when you mouse over it in-game.
Properties	Does this element have special properties? At the minimum you need to put the state here too, see below for possible properties (add them together with +).
LowPressure	If the element drops below this pressure it will transition (set to IPL to never transition).
LowPressureTransition	The element to transition into when pressure is below the threshold (set to NT to never transition).
HighPressure	If the element goes above this pressure it will transition (set to IPH to never transision).
HighPressureTransition	The element to transition into when pressure is above the threshold (set to NT to never transition).
LowTemperature	If the element drops below this temperature it will transition (set to ITL to never transition).
LowTemperatureTransition	The element to transition into when temperature is below the threshold (set to NT to never transition).
HighTemperature	If the element goes above this temperature it will transition (set to ITH to never transition).
HighTemperatureTransition	The element to transition into when temperature is above the threshold (set to NT to never transition).
Update	The update function. This is what controls how your element reacts with other elements.
Graphics	The graphics function, This controls any fancy effects. If your element is only one solid color, you don't need this.

Menu sections

These are used for the MenuSection property.

SC_WALL

SC_ELEC

SC_POWERED

SC_SENSOR

SC_FORCE

SC_EXPLOSIVE

SC_GAS

SC_LIQUID

SC_POWDERS

SC_SOLIDS

SC_NUCLEAR

SC_SPECIAL

SC_LIFE

SC_TOOL

SC_DECO

.Property Constants

These are used for the Properties property.

TYPE_PART

Used in powders.

TYPE_LIQUID

Used in liquids.

TYPE_SOLID

Used in solids / misc elements.

TYPE_GAS

Used in gases.

TYPE_ENERGY

Used in energy particles.

PROP_CONDUCTS

Allows an element to automatically conduct SPRK, requires PROP_LIFE_DEC.

PROP_BLACK

Elements with this property absorb photons of any color.

PROP_NEUTPENETRATE

Elements can be displaced by neutrons (observe behavior of wood with neutrons to see).

PROP_NEUTABSORB

Element will absorb neutrons.

PROP_NEUTPASS

Element will allow neutrons to pass through it.

PROP_DEADLY

Element will kill stickmen and fighters.

PROP_HOT_GLOW

Element will glow red when it approaches it's melting point.

PROP_LIFE

Unused.

PROP_RADIOACTIVE

Element will have a radioactive glow, like URAN or PLUT. Also, deadly to stickmen.

PROP_LIFE_DEC

The "life" property of particles will be reduced by 1 every frame.

PROP_LIFE_KILL

Particles will be destroyed when the "life" property is less than or equal to zero.

PROP_LIFE_KILL_DEC

When used with PROP_LIFE_DEC, particles will be destroyed when the "life" property is decremented to 0. If already at 0 it will be fine.

PROP_SPARKSETTLE

Allows sparks/embers to contact without being destroyed.

PROP_NOAMBHEAT

Prevents particles from exchanging heat with the air when ambient heat is enabled.

PROP_DRAWONCTYPE

Set its ctype to another element if the element is drawn upon it (like what CLNE does).

PROP_NOCTYPEDRAW

When this element is drawn upon other elements, do not set ctype (like STKM for CLNE).