Keyframe rope

This is a preserved entity in
If the game has round restart mechanics this entity may not behave as expected.

move_rope and keyframe_rope are point entities available in all Source games.

Class hierarchy
CRopeKeyframe ↳CBaseEntity
rope.cpp

It is an entity that marks a point in a rope. This entity can be shown as keyframe_rope or move_rope, but the two are completely identical in code.

Traditionally, the first entity in a rope chain is a move_rope, with the following ones being keyframe_ropes. This arrangement is required for Hammer to display the rope preview, unless you're using Hammer++, TeamSpen's Hammer Addons, or another custom FGD or Hammer build which changes this. Regardless, the game itself does not care which combination is used.

Tip:Holding ⇧ Shift while moving a properly named keyframe_rope will create a new keyframe_rope entity that is automatically connected to the previous keyframe. Also, deleting a keyframe_rope within a connected series will update the other entities to re-connect to the next entity in the series.

Note:In and , this entity will automatically have festive lights applied to its model during the winter holiday season. These lights are purely cosmetic and do not emit light. This can be disabled in via tf_gamerules.

Todo: See if this can also be disabled in

Warning:This entity cannot be parented in multiplayer titles in which it's a preserved entity. In , this can be fixed with VScript by assigning the following script to any rope entity that needs to move.

if (!("RopeFix" in getroottable()))
{
	::RopeFixListener <- SpawnEntityFromTable("logic_eventlistener", 
	{ 
		eventname    = "teamplay_round_start",
		IsEnabled    = true,
		OnEventFired = "worldspawn,RunScriptCode,RopeFix.SpawnRopes(),-1,-1",
	});
	RopeFixListener.KeyValueFromString("classname", "move_rope"); // preserve
	::RopeFix <-
	{
		SpawnRopes = function()
		{
			local table = {}		
			local len = ropes.len();
			for (local i = 0; i < len; i++)
				table[i] <- { move_rope = ropes[i] };
			SpawnEntityGroupFromTable(table);
		},
		ropes = [],
	};
}

function OnPostSpawn()
{
	local kv = 
	{
		origin       = self.GetOrigin(),
		angles       = self.GetAbsAngles(),
		targetname   = NetProps.GetPropString(self, "m_iName"),
		parentname   = NetProps.GetPropString(self, "m_iParent"),
		spawnflags   = NetProps.GetPropInt   (self, "m_spawnflags"),
		NextKey      = NetProps.GetPropString(self, "m_iNextLinkName"),
		Slack        = NetProps.GetPropInt   (self, "m_Slack"),
		TextureScale = NetProps.GetPropFloat (self, "m_TextureScale"),
		Subdiv       = NetProps.GetPropInt   (self, "m_Subdiv"),
		ScrollSpeed  = NetProps.GetPropFloat (self, "m_flScrollSpeed"),
		RopeMaterial = NetProps.GetPropString(self, "m_strRopeMaterialModel"),
	}
	
	local segments = NetProps.GetPropInt(self, "m_nSegments");
	if (segments == 10)
		kv.Type <- 0;
	else if (segments == 4)
		kv.Type <- 1;
	else if (segments != 5)
		kv.Type <- 2;
		
	local lockedpoints = NetProps.GetPropInt(self, "m_fLockedPoints");
	if (!(lockedpoints & 2))
		kv.Dangling <- 1;
		
	local flags = NetProps.GetPropInt(self, "m_RopeFlags");
	if (flags & 32)
		kv.NoWind <- 1;
	if (flags & 16)
		kv.Breakable <- 1;
	if (flags & 4)
		kv.Collide <- 1;
	if (flags & 2)
		kv.Barbed <- 1;
	
	RopeFix.ropes.append(kv);
	
	self.KeyValueFromString("classname", "kill_rope"); // don't preserve
}

Todo: Test in , which also has vscript since the 2025 update (the event to listen for will need to be changed).

Keyvalues

Name (targetname) <string>

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also: Generic Keyvalues, Inputs and Outputs available to all entities

Next KeyFrame (NextKey) <targetname>

Name of the next keyframe along this keyframe path.

Slack (Slack) <integer>

How much extra length the rope has (by default it has the length between its two endpoints in the editor).

Type (Type) <integer choices>

Rope type.

• 0 : Rope
• 1 : Semi-rigid
• 2 : Rigid

Subdivision (Subdiv) <integer>

Number of subdivisions between each rope segment. Maximum value is 8. Higher values make smoother ropes, but are slower to render.

Barbed (Barbed) <boolean>

Test effect that makes the rope look sharper and more barbed.

Width (1-64) (Width) <float>

Width of the rope. Decimal values lower than 1 may also be used.

Texture Scale (TextureScale) <float>

This changes the texture resolution. The default resolution is 4 pixels per inch. Larger values stretch the texture and smaller values scrunch it up.

Scroll Speed (ScrollSpeed) <float> !FGD

Change the speed at which the texture scrolls.

Collide with world (Collide) <boolean>

If set, the rope collides with world. Ropes never collide with anything else.

Start Dangling (Dangling) <boolean>

If set, the rope starts out detached from its target endpoint.

Breakable (Breakable) <boolean>

If set, the rope can be detached from either endpoint when shot.

Note:If collide with world is set, the rope will not appear to break if the endpoint touches world geometry. This includes touching vertices and edges of brushes as well as being placed inside them.

Rope Material (RopeMaterial) <material>

The material to use when rendering the rope.

Note:Source will not render ropes using the vanilla cable/chain.vmt material, due to the Cable shader not supporting transparency.

Rope Shader (RopeShader) <integer choices> !FGD 

Deprecated.
Legacy method of choosing rope material.

• 0 - Cable
• 1 - Rope
• Else - Chain

UseWind (UseWind) <boolean> (in all games since )

When set to yes, the rope sways with the settings specified in the env_wind entity. Replaces "Disable Wind" in games post Alien Swarm.
This is very expensive, and when overused can cause the world to not render properly, while the console continuously spews out "Scene is too complex".
If you need to have swinging ropes, it might be less expensive to make a model of a rope, that is animated via bones.

Disable Wind (NoWind) <boolean>

If set, the rope will no longer act as though it's being affected by wind.

Position Interpolator (PositionInterpolator) <integer choices> 

Deprecated.
Curve Type. Only used by Hammer, and not parsed in-game, so should be left at the default of 2 to ensure accurate rope previews. !FGD for keyframe_rope.

• 0 : Linear
• 1 : Catmull-Rom Spline
• 2 : Rope

Speed (unused) (MoveSpeed) <float> 

Deprecated.
Only used by Hammer, and not parsed in-game. FGD default is 64.

Flags

Auto Resize : [1]

Allows the rope to "stretch" as the entity moves.

Inputs

SetScrollSpeed <floatRedirectInput/float>

Set the speed at which the texture scrolls.

SetForce <angleRedirectInput/Vector>

Apply a force instantaneously to the rope. The parameter should be a vector containing the force to be applied (X Y Z).

Break

Break the rope, if it's marked to do so.