Areas rollout
Overview
The areas rollout is used to define boundaries within which items from the Geometry list are scattered. There are 5 types of areas that can be used in combination in a single Forest object:
- Splines.
- Objects
- Forests
- Paint.
- Surfaces.
Depending on the type, an area can be set to either Include or Exclude scatter items. Include is an additive mode that creates items within the region, Exclude is subtractive, removing items from the region. The table below illustrates the modes available for each area type.
| Area Type | Include | Exclude |
|---|---|---|
| Spline | ||
| Object | ||
| Forest | ||
| Paint | ||
| Surface |
Surfaces allow you to scatter items on uneven surfaces, it is possible to toggle surface on and off from the areas rollout but adding new surface areas and editing the parameters is handled in a Surfaces rollout .
Procedures
To create a new Forest object based on a spline
-
Open the Create Panel and select iToo Software from the object subcategory list.
-
Click
and then click any spline in the viewport. -
Open the Modify Panel and make any necessary adjustment to the spline's settings from the Area rollout.
To create a new Forest object based on a surface
- Open the Create Panel select iToo Software from the object subcategory list.
- Click and then click a surface in the viewport.
- Open the Modify Panel and make any necessary adjustment to the settings from Surface rollout.
To add a new closed spline area
- Open the Areas rollout.
- Click
found below the Areas List. - Pick a closed spline from the scene.
To add a new open spline area
- Open the Areas rollout.
- Click found below the Areas List.
- Pick an open spline from the scene.
- Adjust the Thickness value to define the width to scatter objects either side of the spline.
To add a new paint area
To use a paint area you must also have a Surface area set to XY mode but this should be switched off in the Areas list to restrict the scatter to only the painted regions.
-
Open the Areas rollout.
-
Click
found below the Areas List. -
Click
to open the Painter Settings. -
Set the Min and Max brush size, if you are using a tablet turn on Enable Pressure Sensitivity to use pen pressure to control the brush size.
-
Click
and paint on the surface in the viewport.
-
Click
and paint on the surface in the viewport to erase paint areas.
To convert a paint area to splines
- Click
. - Modify the spline using 3DS Max's standard spline modelling tools. 3. If necessary, click
to restore the spline to a paint area (This can be done with any spline object).
To exclude scattered items using splines
In order to work correctly, exclude areas need to be above an include area in the Areas List. To change the order of areas use 
.
- Open the Areas rollout.
- Click found below the Areas List.
- Pick a spline from the scene, if it is an open spline enter a Thickness value.
- Click Exclude.
To exclude scattered items using an object
-
Open the Areas rollout.
-
Click
found below the Areas List. -
Pick any geometry object from the scene. Where the object overlaps an include area the scatter items will be removed.
-
To improve accuracy for large scenes increase the Resolution value (default is 512px).
-
To Increase or decrease the distance between scattered items and the object, adjust the Scale value.
You can also use groups but this is recommended only when the objects are close together. If you need to use multiple objects that are a large distance apart, assign each one as a separate area.
To exclude scattered items using another Forest object
- Open the Areas rollout.
- Click
found below the Areas List. - Select a Forest object from the scene.
- Adjust the Scale value if necessary to change the exclusion size around each tree.
- Change Falloff > Exclude values for Density and scale (see below).
To create a separate region around the base of each tree.
- Clone the Forest Object used in the last steps
- Select the Forest area from the list and click on Invert Curve. Adjust falloff, Add Geometry items and Image Mode as required.
To add scale and density falloff along a boundary
Using falloff controls it is possible to affect the density and scale of objects near an area's boundary.
- Click Falloff > Density and Falloff > Scale.
- Enter Include Range values to define the distance affected measured from an include area's boundary.
- Enter Exclude Range values to define the distance affected measured from an exclude area's boundary.
- The default falloff setting is linear, to change the falloff curve click
. - The falloff graphs have the range on the X Axis (from 100% to 0 %) and the Scale or Density percentage on the Y Axis (from 0% to 100%).
To add scatter items around the perimeter of an exclude object
- Add a Spline, Paint or Surface include area.
- Add an Exclude area above the include area in the Areas list.
- Turn on Falloff > Density and/or Falloff > Scale and enter an Exclude Range value.
- Click Invert Curve. This will reverse the effect of the falloff curve generating items only around the perimeter of the exclude object.
To override the geometry used in an individual area
- Select the Area to parameterised from the Areas List.
- Click Plants > Select Models.
- Click
and tick the models to use from the Select Models menu. Click OK.
To limit the scatter using material IDs
- For this feature to work, a Surface must be assigned in the Surface rollout and Forest must be set to X/Y Mode.
- In the Mat. ID list box, enter the Material ID numbers of the faces you wish to use to scatter objects
- To add multiple IDs simply add a list, ensuring there is a space between each value.
To override the distribution map used in an individual area
- Adjust the scale of the distribution map by adjusting Override Dist. Map > Scale.
- Adjust the density of the distribution map by adjusting Override Dist. Map > Threshold.
- Apply a new distribution map to the selected area by dragging a map to the Distribution Map Slot.
To prevent scattered items from "leaking" outside an area perimeter
- For V-Ray users, set Boundary Check node to Edge.
Please be aware that Edge Mode is not compatible with V-Ray proxies.If you wish to reduce file sizes and use Edge Mode it is recommended to use XRef objects instead.
- For Arnold and Corona
-
users, set Boundary Check mode to Edge.
-
Add a Forest Edge map to the Opacity or Cutout map slot of all the object's materials. You can automate this process for objects with large numbers of materials using the Material Optimiser tool.
- For all other renderers, set Boundary Check node to Size. To create large areas with well-defined boundaries, please refer to the Grass Edges tutorial.
Interface
Areas List
The areas list details all the items being used to define the scatter region. The order is important, areas are processed from the bottom of the list upwards, an exclude area will only affect areas that are below it in the geometry list.
- In Forest Pack 7 and earlier, areas are not available when working on Custom Edit mode or using UV Surfaces. In Forest Pack 8, areas can be used with UV Surfaces, but not Custom Edit mode.
- It is important not to overlap multiple Include areas. Overlapping areas duplicates geometry and the issue is not always obvious in the viewports, but you may get strange results in the render because of the coplanar faces.
| Icon | Name | Description |
|---|---|---|
| Add spline area | Adds an include/exclude area defined by a spline object. |
| Add object area | Adds an exclude area defined by a geometry object. |
| Add forest area | Adds an exclude area defined by a Forest Pack object. |
| Add paint area | Adds an include/exclude area by painting a spline using the mouse or tablet |
 | Add linked areas | Adds an area referenced in another Forest Pack object |
 | Delete selected area | Removes the selected area. |
| Move up | Move the selected area up. |
| Move down | Move the selected area down |
Selecting an area from the list will change the available options in the Properties group. Some properties are common to all types of areas, while other are unique:
Spline Area Properties
On
When active turns the current area on. If unselected the area will be ignored when calculating the scatter regions.
Name
The name of the area. Default behaviour is to inherit the name of the source object but it can also be edited manually.
Include
When active the area creates items within the region defined by the spline.
Exclude
When active the area removes items within the region defined by the spline. Only items generated by areas below it in the Areas List will be affected.
Spline
Displays the name of the selected spline. Click this to pick a new spline from the scene.
Thickness
Used with open splines to define the width of the path in which items are scattered.
Force Open Splines
When enabled, all splines in the Area are treated as open splines. A distance either side of the spline is determined using the Thickness parameter.
Convert to Paint
Converts the Spline area to a Paint area.
Object Area Properties
Object areas allow you to use any geometry to exclude scattered objects. Object areas are optimised for high polygon models and work by generating a black and white bitmap map by projecting the geometry onto the surface along the world Z axis.
Object
Displays the name of the assigned objects. Click this to pick a new object from the scene.
Top Limit
Defines a height above which the object's geometry is ignored when calculating the exclusion map .This feature is typically used for objects that are wider at the top than at the bottom.
Resolution
Defines the size of the bitmap. Higher numbers result in greater accuracy typically required when using large models. Default value is 512px.
Scale
Scales the exclusion effect. Values of less that 100% will move scattered items closed to the object, values greater that 100% will push scattered items away from the object.
Forest Area Properties
Forest objects work in a similar way to Object areas allowing the use of a Forest object to create an exclude area.
Forest
Displays the name of the assigned Forest object. Click this to pick a new forest from the scene.
Shape
Select from Sphere or Mesh to define the geometry used to create the exclusion effect. Sphere use a virtual bounding sphere that is much faster though less accurate. The size of the sphere can be adjusted using the Scale value of the area or by changing the Collision Radius parameter for the Items found in the Geometry Rollout .
Mesh mode uses the full geometry to calculate the exclusion effect. The approach is more accurate but can be slower when using dense geometry.
Resolution
Defines the size of the bitmap. Higher numbers result in greater accuracy typically required when using large models. Default value is 512px.
Scale
Scales the exclusion effect. Values of less that 100% will move scattered items closed to the object, values greater that 100% will push scattered items away from the object.
Paint Area Properties
Paint areas allow you to paint include and exclude regions with a mouse or tablet directly onto the terrain. Paint areas require a Surface set to XY mode.
Include
When active the area creates items within the region defined by the spline.
Exclude
When active the area removes items within the region defined by the spline. Only items generated by areas below it in the Areas List will be affected.
Paint
Paint on a surface in the viewport to add to the current area.
Erase
Paint on a surface in the viewport to subtract from the current area.
Settings
Click to open the brush settings. From this menu you can adjust the size and pressure sensitivity of the brush and erase modes.
Brush Size
A quick way to change the size of the paint brush without needing to open the full settings (FP8 only)
Preview Falloff
When active the falloff effect is visible while painting (enabled by default).
Convert to Spline
Converts the Paint area to a Spline area.
Linked Area Properties
Linked areas allow you to use an area that's contained inside another Forest Pack object, inheriting their parameters. For example, you could assign a Spline in a "master" Forest object, and use it as an area in other Forest objects, without reassigning the spline multiple times.
Parameters specific to each type of Area are inherited (as Spline/Object, Thickness, etc.), while common parameters (as Falloff) are local and can be modified. Not all combinations may work. I.e. a linked "Object Area" can be used only as Exclude, not as an Include area.
Forest
Click to select another Forest Object from the scene.
Area
A drop down list containing all the areas of a linked object. Select the one you wish to use.
Surface Area Properties
Due to the large number of options the majority of the surface areas settings are found in a separate Surfaces rollout. They do however display in the Areas List and can be toggled on or off from the Areas rollout.
On
Turns the surface on or off.
Surfaces are often used to define the scattered item's position on the Z axis in conjunction with splines and paint areas to define the region on the X and Y axes. Occasionally you may find that the full terrain is filled with items,even though there are spline areas in the Items List. If this is the case the usual problem is because the Area is on, when using surfaces with other Include areas it is important to turn the Surface off.
Common Properties
These properties are found in all area types.
Select Models
When active the selected area uses a subset of the models from the Geometry list defined in the Pick menu
Pick
Opens the pick menu. When Select Models is active the current area will use only the models ticked in this list.
Override Distribution Map
Used to override the global distribution map.
Scale
Scales the distribution map only for the selected area.
Threshold
Adjusts the threshold only for the selected area.
Material ID
Limits the scatter surface to use faces with only the material IDs listed. To use multiple IDs, simply leave a space between them.
Falloff Affect
Adjusts the strength of the density and scale falloff curves. Setting this value to zero disables the effect completely.
Invert Curve
Inverts the falloff curve. Commonly use to create scatter items around boundaries and the perimeter of exclude areas.
Boundary Checking
Forest Pack 4.3 can use 3 potential modes to determine if an object falls outside of the scatter area and is removed.
- Point. Uses the item's pivot point to check if outside the scatter area. If true the entire item is removed and you may get overlaps.
- Size. Uses the item's width and collision radius to check if outside scatter area. If true the entire item is removed and you won't get overlaps but the boundary can be uneven if the item's size is too large.
- Edge(V-Ray only): Uses the lowest Z Vertex of each of the item's individual elements to check if outside the scatter area. If true only the individual element is removed creating a clean edge, without slicing the geometry. Note that when using edge mode, an element is defined as a group of connected faces that share the same material ID. These are the same elements used by Forest Color .
To improve viewport performance edge trimming is calculated only at render time. This means the effects of the this mode will not be previewed in the viewports. However, previews can be enabled by holding down the left CTRL key and clicking on the Edge radio button .
Please be aware that Edge Mode is not compatible with V-Ray proxies.If you wish to reduce file sizes and use Edge Mode it is recommended to use XRef objects instead.
Project Axis (UV Mode)
Forest Pack 8 and upwards can use areas in UV mode. This option allows you to select the projection axis of an area, based on the Forest Object's local coordinate system.
- All areas are projected in a direction (X/Y/Z), according to the Area->Projection Axis parameter.
- Area->"Distribution Map" parameters are not supported in UV mode.
- Edge Mode requires a Spline or Paint area. It cannot be used directly over the surface.
- Changing the Projection Axis in a non-empty Paint area may generate unexpected results. Always select Projection Axis before starting to paint.
Falloff
Density
When on, items will change density as they approach a boundary. The distance from the boundary is controlled by the include and exclude range values and the density is defined by a falloff curve.
Scale
When on, items will change scale as they approach a boundary. The distance from the boundary is controlled by the include and exclude range values and the density is defined by a falloff curve.
Edit Curve
Edits the the falloff curves for the density and scale effect. There are separate curves for scale and density.
Include
Sets the range for the falloff effect on the perimeter of Include splines and surfaces.
Exclude
Sets the range for the falloff effect on the perimeter of Exclude objects, forests, and splines.
Affect Height only
When on the scale falloff effect only affects the height of the items. Dimensions on the X and Y axes remain unchanged.