Creating New Life with the Expotron and Max, Part 4: Attachment Points

This is Part 4 of my tutorial on bringing new creatures to NWN2 using 3DS Max and the Expotron. Part 1 of this series may be found here.

Attachment points on a creature model are dummy objects to which certain non-animating meshes or visual effects can attach themselves to. They are part of a creature’s main skeleton hierarchy (the skeleton that controls the body mesh), although they do not count toward the fifty-four bone limit. These attachment points have standard names that the game engine expects of them. Not all attachment points are present in each creature, although most of them usually are. New creatures should have as many attachment points as necessary in their skeletons as well.

Below is a table listing a number of attachment points, the approximate position of each point, which bone each point typically connects to, and any special usage in the game. Visual effects may be applied to any of the attachment points, so unless there is a particularly noteworthy usage of an attachment point, its entry under Usage will be left blank.

Attachment Point	Position	Attached Bone	Usage
ap_halo	above the head	Head	status icon vfx (e.g., berserk icon)
ap_forehead	front and center of the head at around the hairline	Head	placement of hair
ap_eye_right	front of right eye	Head	eye vfx (e.g., lich eyes)
ap_eye_left	front of left eye	Head	eye vfx (e.g., lich eyes)
ap_ear_right	just outside the center of the right ear	Head
ap_ear_left	just outside the center of the left ear	Head
ap_mouth	inside and center of mouth or just outside it	Head	breath weapon vfx
ap_camera	varies with each creature model, but usually inside or somewhere at the front of the head	Head	position that a camera will point to during close-ups of the creature in cutscenes
ap_torso	front and center of chest	Ribcage
ap_back	back and center of thoracic region of the spine	Ribcage
ap_hand_right	center of palm of right hand	RArm1Palm	vfx of cast spells, placement of wielded weapons
ap_hand_left	center of palm of left hand	LArm0Palm	vfx of cast spells, placement of wielded weapons
ap_shield_left	center and back of left forearm	LArm02	placement of shield when equipped
ap_pelvis	center of the pelvis	root bone of the body’s skeleton
ap_tail_tip	tip of the tail	last tail bone
ap_knee_right	front of right knee	RLeg1
ap_knee_left	front of left knee	LLeg1
ap_foot_right	between ankles of right leg	RLegAnkle
ap_foot_left	between ankles of left leg	LLegAnkle

It should be noted that ap_halo and ap_camera never change from their initial position relative to the creature even when the creature moves in the game.

If a creature does not have ap_hand_right, its spells will appear to shoot from the southwest part of the area it is in, which is where the (0,0,0) coordinate position is.

Aside from the position of attachment points, their orientation is important as well. For example, if ap_mouth is oriented incorrectly, breath weapon particles will shoot in the wrong direction. Similarly, weapons attached to ap_hand_right and ap_hand_left will not be held properly if these attachment points are angled wrongly.

Particle emitters positioned at a wrongly oriented ap_mouth may cause breath attacks to miss their targets.

In my next blog post, I will show how to make a skeleton complete with attachment points. I will also discuss collision spheres and how to make them. Finally, I will show how to use the Expotron to export all these resources so that the creature can be viewed in the toolset and in the game.