Houdini 19.0 Nodes VOP nodes

For Loop VOP node

Runs the VOP nodes inside its subnetwork until a given condition is true.

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This operator contains other VOP operators. The code for the contained operators is executed repeatedly in a loop until the specified condition is met.

Use this operator to repeat the same sequence of code many times. Be careful when using this operator to ensure that the condition will eventually be met. Otherwise an endless loop can result. Such endless loops can be interrupted within Houdini, but can result in renders that never finish.

Any value that you wish to modify inside the For Loop operator must be provided as an input. The outputs of the For Loop operator will contain the modified versions of the inputs once the loop exits. The actual values wired into the For Loop operator inputs are never modified, and so can be connected to other operators in the network, but remember that the values from these operators will always be the values unmodified by the For Loop operator.

The looping of this operator is always controlled by a simple counter. The While Loop VOP provides a more flexible construct that can be used to exit based on any condition, as opposed to using a simple counter.

All connected inputs mimic the properties of the output wired into them. They adopt the same help label and name as the output connected to them. If multiple outputs with the same name are connected, the names of the inputs are automatically incremented to make them unique.

The list of outputs depends on the inputs connected to the Subnet Output operator contained in this operator. The data type and name of each output will match the corresponding input of the Subnet Output operator.


You can use the _i value on the subinput (Initial Value when Show Full Input and Output Names on VOP Nodes is enabled in the main preferences) to access the loop iteration variable.



Specifies whether to use a Float or Integer type counter.


This sets the type of comparison to use between the Initial Value and the End Value to determine if it is time to exit the loop.

Integer/Float Initial Value

This is the initial value given to the counter.

Integer/Float End Value

The loop exits when the counter is compared to this value and meets the criteria set in the Test parameter.

Integer/Float Step Size

After each loop, the counter value is increased by the Step Value. This number can be negative to have a decreasing counter value, but remember to set the Test parameter appropriately.


Next Input

Up to 64 inputs can be connected here.



This is a method for applying rotations to curve segments. It utilizes the For Loop Vex Node to compute segments and apply rotations and position, according to point numbers.

See also

VOP nodes