Trapcode Form

Using Curves

Curves (formerly called Quick Maps) are a fast and fun way to change the particle grid. They can be used to map opacity over X, Y or Z axes, change the size of the particles over an axis, or change properties like dispersion and fractal strength. Curves are convenient because they are generated within Form and do not need to be created beforehand on a separate After Effects layer.

Curves can be used to control particle size (Particle > Size Curve), opacity (Particle > Opacity Curve), dispersion (Disperse and Twist > Disperse Strength Curve), the strength of fractal displacement (Fractal Field > Fractal Strength Curve), and the strength of the reaction to audio (Audio React > Reactor [all 5 Reactors] > Strength Curve).

NOTE: Quick Maps are always applied to the grid first, before any displacement fields are applied to the form.


The Curves interface.

Map Over pop-ups: Each Curve will also have an accompanying “map over” pop-up, which determines the axis along which the curve adjustment will be applied. Each map over pop-up has 5 options.


  • Off: Tells Form that the Curve will not be used to control this property.
  • X: Maps the accompanying Curve adjustment over the X axis.
  • Y: Maps the accompanying Curve adjustment over the Y axis.
  • Z: Maps the accompanying Curve adjustment over the Z axis.
  • Radial: Maps the accompanying Curve adjustment around the whole form, radially.
usingcurves3 Opacity Over set to Off
usingcurves5 Opacity Curve used in these examples
usingcurves6 Opacity Over set to X
usingcurves7 Opacity Over set to Y

Opacity Over set to Z


Opacity Over set to Radial.

Note that in this example, the form has been adjusted such that the Z axis represents the vertical axis of the form.

Map Offset: Offsets the curve, raising the values up or down. Offset can be keyframed, which effectively allows you to animate the properties to your liking.

Using Curves: Curves are special graphs in the interface that allow you to specifically control certain properties.


Curve Basics: In each instance of the curve, the controls behave in a similar way. The vertical axis of all graphs is used to indicate the amount of an attribute. The horizontal axis is used to determine where those values fall across the form particles, based on the value chosen in the corresponding map over pop-up.

For example, if we use the following curve for the Size Curve, and change the Size Over pop-up to X, the curve will change the size of the form particles along the X (horizontal) axis. As the curve starts at the top and descends as it goes to the right, so too will the size of the particles start at their full value (i.e. the current Particle > Size value) on the left side of the form, and reduce in size from left to right.



Notice how the size of the particles shrinks from left to right (because the curve is set to affect the particles along the X axis). This corresponds to the curve above, which descends from left to right.

Animating Curves: Curves in Form can now be animated. You can create two completely different Curves, and Form will interpolate between them over time. Simply click the stopwatch next to the Curve to record the current shape of the Curve graph, and then animate this as you would any other After Effects property.


Curve Presets: In the upper right corner of the curve interface, you will find a presets drop down with many common graph types. While you get the most control from drawing your own curves in the graph (discussed below), using the curve presets can provide a faster shortcut to common curve shapes, or provide a jumping off point that you can customize with your own drawing. Note that the presets become significantly more powerful when using the other interface controls in the graph (discussed below).


There are six preset curves to choose from:

  1. the top preset resets the curve, as it sets the attribute to be at full value for the life of the particle.
  2. this preset creates a diminishing value over time
  3. this preset causes a quicker initial increase in value and then a slower reduction
  4. this preset causes a smooth rise and a smooth reduction in value
  5. this preset causes the value to have an eased, but sudden reduction around the middle of the life of the particle
  6. this preset creates a similar effect to preset #5, but the reduction in the middle of the life of the particle is slightly more gradual, and the end of the life has several "spikes " of a high value. This preset is often used for the Opacity curve, as it can create a sparkle right before the particle dies.

Drawing Curves Manually: The most powerful way to create curves is to manually draw them in with your mouse in the main curve window. Simply click and drag in the curve area with the pencil tool, and wherever you click will become the value for that attribute at that place in time in the life of the particle.


A manually-drawn curve.

When manually drawing curves, you also have two tools: a pencil (default), and a pen. The pencil allows you to draw the path as you would like. The pen tool allows you to use bezier control points on a curve to achieve the desired curve in the graph. Note that simply selecting the pen tool will also instantly apply a significant amount of smoothing to your curve.

These tools can also be used in tandem. For example, a curve can be quickly drawn manually with the pencil, and then by clicking the pen tool, the rough curve becomes smoother and easier to adjust.


After creating the above curve with the pencil, and then clicking the pen tool.

Curve Interface Controls: There are a host of tools to assist you in creating the ideal curve.

In the upper right hand corner of the graph, the left-facing arrow allows you to undo the last action performed in the curve. After undoing an action, the arrow will face to the right and will allow you to redo the action just undone.


The Undo/Redo button in the curve interface.

In the far right corner of the curve area is the circular arrow, which is the Reset button. This button allows you to reset the curve to get a fresh start.


The Reset button in the curve interface.

The right side of the interface has Copy and Paste buttons that you can use to mimic behaviors in various graphs throughout Form, and even in other instances of Form in other compositions in After Effects. Simply click the Copy button, and then in another graph, click the Paste button.

NOTE: The Paste button will only be available once a curve has been copied.


The Copy and Paste buttons in the curve interface.

If you are using the pencil, you can click the smooth button to smooth out your results. This feature is gradually iterative, meaning that each time you click it, the curve becomes more smooth.


The Smooth button in the curve interface.


After drawing a curve with the pencil.


After clicking the Smooth button twice.


After clicking the Smooth button 7 times.

Next to the Smooth button is the Randomize button.


The Randomize button in the curve interface.

This usually creates an extremely random curve that would typically be very difficult to create manually.


The results after clicking Randomize.

To the right of the Randomize button, we find the Flip Curve button.


The Flip Curve button in the curve interface.

By clicking the Flip Curve button, the curve is flipped along the horizontal axis.


The initial curve before flipping.


The results after flipping the curve.

Drawing Area: Lets you paint a curve value. As you click and drag over the drawing area with the pencil tool selected, the value is drawn between the bottom and top of the area. Values near the top represent a maximum value, and values near the bottom represent a minimum value.