and 
icons.
{% hint style="info" %}
If a composition contains both types of masks, **inclusive masks are applied first** and then exclusive masks are applied over the remaining instances.
Masks are automatically reordered when toggling their inclusive/exclusive mode in order to reflect this rule.
{% endhint %}
## Paint masks
A *Paint mask* allows you to manually draw the shape of the mask. You draw the shape with a brush, just like you would in Photoshop or similar image editors.
To draw the mask, click the 
icon, then click & drag over your hosts. You can later click the 
icon at any point to continue drawing the mask.
To erase the mask, click the 
icon, then click & drag over the existing shape.
{% hint style="info" %}
Erasing an *inclusive* Paint mask is not the same thing as drawing an *exclusive* Paint mask!
{% endhint %}
| Key | Description |
| ----- | --------------------------------------------------------------------------- |
| ALT | Change the drawing mode when pressed (toggle paint/erase) |
| SHIFT | Draw a straight line |
| CTRL | Maintain pressed and move the cursor laterally to change the brush's radius |
## Area masks
An *Area mask* is a group or a component instance that defines a space under which instances will not be scattered.
To add a new Area mask, click the 
icon and pick a group or component in the model.
| Parameter | Description |
| --------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Mode | Part of the geometry used for masking.
In Faces mode, instances directly below the entity faces will be masked. This is useful to preserve holes in the mask.
In Contours mode, the whole silhouette of the picked entity is used. Only edges are considered, faces do not have any effect.
The direction in which instances are masked.
If unchanged, the default behavior is to use the same projection axis as the composition.
|  ## Path masks A *Path mask* uses a curve with a configurable thickness under which instances will not be scattered.  To add a new Path mask, click the
icon and pick a group/component containing curves.
| Parameter | Description |
| --------------- | ------------------------------------------------------------------------------- |
| Thickness | Lateral distance under which instances are masked |
| Projection axis | The direction in which instances are masked, like for [area masks](#area-masks) |
## Image masks
An *Image mask* uses an external image file to control where instances can be scattered. This is useful to reproduce complex patterns.
To add a new Image mask, click the 
icon and select an image file on your disk.
{% hint style="warning" %}
Image masks rely on the surface hosts having valid [texture coordinates](https://skatter.help.lindale.io/hosts#texture-coordinates). Please make sure that your surface hosts are properly set up.
{% endhint %}
| Parameter | Description |
| ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| File | Image file to use as a mask. |
| Offset | Moves the image along the X and Y axis.
Texture coordinates are traditionally defined in the \[0, 1] range, so an offset of 0.5 usually moves the image by half its size (this convention might not be followed depending on the origin of the texture coordinates).