Crack image Attributes

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The Crack image feature of Fracture allows a user to interactively paint, or assign an image, to define the fracture pattern that is projected through a mesh. This feature is commonly used in creating spider-web fracture pattern for shattering glass.

FFX Fundamentals: fracture types, crack image

Crack image attributes.png


Draw cracks

type bool
default True
Draw the extrapolated splines on the crack plane.

Crack plane indices

Like with the split plane feature, a user can create more than one plane with which to project a crack image through. By default there is a single crack node available. More can be added and are indexed starting at 0. Each crack plane index has its own instance of attributes, covered below, to allow for individual adjustment of attributes on a per plane basis.

The Attribute Editor example below shows that the current node has 3 crack image planes. The first one (0) is expanded to illustrate the available attributes for each crack image plane.

AE crack image multi indices.png

When connected, each of these nodes can be found in the Outliner. By default the naming convention is "crack#".

Crack image multi crack nodes.png


type string
Name of the sketchPlane node assigned to the current index. When a new index is added it does not yet have a crack node (sketchPlane) assigned. Clicking the Connect button will generate the node. If, at any time, the source geometry is scaled the Refit button will scale to the largest bounding box axis.

Crack image

type color
Attribute that the input image will be connected to. On a new crack image node there won't yet be in image connect. Clicking the Paint button will immediately put in you into paint mode. This artisan mode will allow a user to paint (in black&white) on the plane node to define the fracture pattern that will be projected through the mesh.

Crack image texture not saved.png

On a new crack image projection the first thing you will notice is that painting does not update the mesh. In order to see the results, and get real time interactive feedback while painting, you will need to save the current paint operation to file as a texture. In the 3D Paint Tool locate and press the Save Textures button

Save textures button.png

If the current scene is new and has not yet been saved you will see this dialog box.

Scene not saved dialog.png

You must save the scene to continue. Once the scene is saved the texture will be saved, the projected fracture will be visible and you can resume updating the texture via Maya's artisan tools

Crack image texture saved.png

Image threshold

type float
default 0.5
minimum 0.0
maximum 1.0
Minimum pixel value to create a spline from. The image below was applied to a crack image. The pixel values of each line, from left to right, are: 20, 40, 60, 80, and 100

Pixel value.png

As the pixel value attribute is dialed down the lower values on the image are used.

Erase path distance

type float
default 0.0
minimum 0.0
Erase paths shorter than this distance in pixels.

Reduction tolerance

type float
default 2.0
minimum 0.0
Merge distance in pixels.

Non-uniform refit

type bool
default False
When toggled on this option allows a sketchPlane to scale non-uniformly to the bounding box when the Refit button is pressed.


There are handful of buttons that are located within the crack image attribute group.


Create, and connect, a sketchPlane node that will be used to paint on before projecting the cracks onto the mesh.


Based on whether or not the Non-uniform refit option is set to; scales a sketchPlane up to match either the largest dimension of the objects bounding box or the XY bounding box.


Initiates Maya Artisan mode to allow a user to paint on the sketchPlane node.


Deletes the current crack image and its associated sketchPlane node.


Creates a new crack image group. The sketchPlane node is not connected until the Connect button is used.

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