Houdini 12 Basics

The value ladder lets you interactively change numeric values with mouse movements.

Overview

The value ladder is part of the Houdini user interface that lets intermediate and expert users adjust values quickly.

Using the ladder effectively takes some practice, but once you get used to it, it has certain advantages over other ways of editing parameters.

  • Unlike sliders, the ladder has no default range of values: you can use it to make any size change, from very small to very large. It’s also available in places where sliders won’t fit.

  • Once you start adjusting a value with the ladder, you don’t need to pay attention to it anymore: you can concentrate on the effect of the changes in the viewer.

How to

  1. Move the mouse over a number in the interface and press MMB (see below for examples of where you can open a ladder).

    The “ladder” is a vertical stack of numbers representing how much to add/subtract when you move left or right.

  2. While still holding MMB, drag up or down the ladder to choose the magnitude of the changes you want to make.

    For example, to make very small changes, drag down to the 0.01 box. If you are adjusting a rotation, with ranges up to 360 and beyond, you may want to move up to the 10 box.

  3. While still holding MMB, drag left or right to change the value. Each movement of the mouse left or right subtracts or adds the value in the box.

    If you decide you want a different magnitude, drag back to the ladder and move up or down.

  4. Release MMB to confirm the change.

Where you can use the ladder

In general, you can get a value ladder anywhere in the interface by moving over an editable number and pressing and holding MMB.

WhereHow
In the parameter editor
  • Press MMB on a parameter name to edit all components of the parameter at once.

  • Press MMB in a text box to edit just that value.

  • When editing an expression, press MMB on a number in the expression to edit it.

In toolbars and option windows

Press MMB on any numeric text field.

On handles

Press MMB on a handle part to edit its value.

In the viewer

Scope the channels you want to change. In the viewer, hold J and press MMB to edit the scoped parameters with a ladder.