Collisions

Visionary Render supports basic collision detection and response via the Character Controller, Collision node, and Detect Clashes context menu option.

Character Controller

The character controller can be enabled by clicking on the button in the Toolbar. It creates a capsule around your avatar to detect when it collides with the environment. This is enabled by default in the Start Room and is what permits you to walk around the room and up and down the stairs, etc. without walking through objects and walls.

note

If the character controller is enabled whilst the camera is inside geometry, it will attempt to resolve the collision. If the collision cannot be resolved, a dialog will be shown. To fix the problem, disable the character controller, move the camera away from any geometry in the scene, and try again.

Settings

The character controller can be configured from the Settings window under User Interface > Navigation > Character Controller.

Setting	Description
Character Controller Enabled	Whether to enable game character-style movement, with collision based on a capsule shape around the camera. [default: false]
Collision Enabled	Whether to enable wall collisions. If disabled, the camera will still follow the ground, but will be able to walk through walls. [default: true]
Collision Type	The collision group and mask for the character. The character will collide with objects for which both the character's collision group matches the object’s collision mask, and vice versa. [default: Custom]
Height	Total height of the capsule (including Hover Height). [default: 1.8]
Radius	Radius of the capsule. [default: 0.25]
Eye Offset	Y coordinate offset from the centre of the capsule shape to the camera position. [default: 0.45]
Hover Height	How high off the ground the character capsule shape hovers. Affects stair climbing. [default: 0.4]
Max Slope	Maximum incline the character can climb (degrees). [default: 30.0]
Gravity	Gravitational acceleration. [default: 9.81]
Terminal Velocity	Terminal fall speed. [default: 55.0]
Proxy Target	Node to control rather than the camera. [default: none]

Collision Node

The collision node has several properties that determine how collisions are determined, what type of object it can collide with and which objects are informed of the collision. Right-click on the Assembly that you wish to add collision detection to and select Create > Collision from the context menu.

Properties

Property	Description
Enabled	Whether or not the collision is enabled.
Visible	This can be used to debug collisions when there is unexpected behaviour. To show visuals, Settings > Collision > Debug Draw must also be enabled.
Collision Response	This property is linked to the dynamics and therefore only works with a dynamic license. It allows two objects to collide and trigger a collision without one object pushing the other.
Report	The objects that will be notified about the collision. This report is required to trigger touch/break scripts that are assigned to the parent or other scene objects. None – no collision is reported. This – reports to the parent of the collision node. Other – reports to the object collided with. Both – reports to both objects (default).
Type	This enables you to filter out certain types of object from triggering collisions. All – collision events are triggered when anything touches this assembly. Pickable – collision events are triggered on this assembly when this Collision touches a Pickable type Collision. Picking – collision events are triggered on this assembly when another collision with type Picking touches us. Pick + Pickable – collision events are triggered on both sides of a Collision/Collision event. Click on the Advanced button to customise the objects that trigger collisions.
Mode	Mode is used to specify the collision geometry: Geometry Bounding Box – this is the default setting. It uses the bounding box of the geometry as a collision boundary. Bounding Box – the bounding box allows you to specify a box around the centre point of the parent object. Minimum and Maximum X, Y and Z values are added to provide the size. Sphere – specify a radius and offset position for the spherical collision geometry. Visual – visual will use the geometry for collision. This can be slow depending upon the complexity of the model but is the most accurate. Specifying a different visual can be used to target a lower polygon model that conforms to the shape of the main object. This can be very useful when high polygon geometry is being used and a lower polygon version can be used for collisions. Ray – uses a ray intersection from the assembly, only the first intersection triggers the Collision. The length of the ray can be specified with direction being defined as a unit direction vector. Penetrating Ray – uses a ray intersection from the assembly, all intersections trigger the Collision. The length of the ray can be specified with direction being defined as a unit direction vector. Geometry Convex Decomposition – geometry is processed to create a collision surface. On occasions, this can result in spurious geometry that causes collisions when it shouldn’t. Convex decompositions are used for performance whilst retaining close fit to the model.

Kinematic

The Kinematic drop-down allows for a mass to be applied to an object so that it can have rudimentary physics applied to it. This requires a Dynamics feature license.

Property	Description
Mass	Mass of the object. Set this to a value greater than zero to enable the object to act under dynamics.
Restitution	Coefficient of restitution. The ratio of the final to initial relative velocity between two objects after they collide.
Friction	Coefficient of friction. A value that shows the relationship between the force of friction between two objects and the normal reaction between the objects that are involved.

Context Menu

When collision nodes have been applied within a scene, they can be easily disabled or enabled using the context menu. Enabling or disabling will walk through the tree structure and enable/disable any collision nodes that are beneath it in the tree.

Detect Clashes

Often in scenes its useful to be able to detect whether parts can fit through gaps freely or whether they will collide with doorways, etc. Visionary Render provides a simple one-click method of adding this to a scene. Right-click on the Assembly that you wish to add collision detection to and select Tools > Detect Clashes from the context menu.

This will add a Collision node, Touch Script and Break Script to the Assembly and create a collision material called CLASH_assembly_name – i.e. CLASH_Solid_81.

When the part is moved, any object it collides with will be turned white whilst it is in contact. This colour can be changed as per changing any material colour.

warning

The Detect Clashes script was modified in the 2023.1 release to handle simultaneous collisions and other edge cases. This change is not automatic for existing scenes so any Touch events created before this release should be updated to use tools.clashDetectionTouch(__Self, __Other, __Script). Any Break events should be updated to use tools.clashDetectionBreak(__Self, __Other).