The taxonomy organizes natural-language
relations into learnable constraint types (positional, orientational,
and height-based) such as chair against wall, table aligned with sofa,
or lamp on top of desk.
\[
\begin{array}{llll}
\hline
\textbf{Constraint Type} & \textbf{Constraint Name} & \textbf{Method} & \textbf{Description} \\
\hline
\text{Position-based} & L_{\text{distance}}(p_i, p_j, d_{\min}, d_{\max}) & \text{LayoutVLM} & \text{Distance between the two assets should fall within the range } [d_{\min}, d_{\max}]. \\
& & \text{Ours} & \text{Distance between two objects to } [d_{\min}, d_{\max}]\text{, where bounds are inferred from reach and clearance requirements based on anthropometric data.} \\
& L_{\text{against wall}}(p_i, w_j, b_i) & \text{LayoutVLM} & \text{Place an asset against wall } w_j. \\
& & \text{Ours} & \text{Places the object against a specific wall while considering accessibility and clearance requirements for nearby interactions.} \\
\hline
\text{Orientation-based} & L_{\text{align with}}(p_i, p_j, \Theta) & \text{LayoutVLM} & \text{Align two assets at a specified angle } \Theta. \\
& & \text{Ours} & \text{Aligns the rotations of two objects; the angle parameter } \Theta \text{ reflects task-oriented alignment (e.g., parallel or perpendicular configurations for joint use).} \\
& L_{\text{point towards}}(p_i, p_j, \Theta) & \text{LayoutVLM} & \text{Orient one asset to face another with an offset angle } \Theta. \\
& & \text{Ours} & \text{Adjusts orientation so that an object's front faces the target, with } \Theta \text{ encoding preferred viewing or interaction directions (e.g., facing a desk, or seating area).} \\
\hline
\text{Height-based} & L_{\text{on top of}}(p_i, p_j, h) & \text{LayoutVLM} & \text{Position one asset on top of another.} \\
& & \text{Ours} & \text{Defines a vertical stacking relationship for placing smaller objects on surfaces while keeping sufficient interaction area.} \\
\hline
\end{array}
\]
Spatial Constraint Taxonomy for Behavior-Aware Anthropometric Scene Generation, comparing our behavior-aware, anthropometrically grounded constraints with the geometric relations [4].
· Notation: \(p_i, p_j\) object poses; \(w_j\) wall index; \(b_i\) object bounding box; \(d_{\min}, d_{\max}\) minimum/maximum center distance; \(\Theta\) relative angle; \(h\) height offset.
Spatial constraint taxonomy, animated · each of Table 1's five losses pulls its movable object from a violating placement (high loss) into the satisfied one (loss → 0); the coloured arrow is the loss's negative gradient. Grouped by type — position (blue), orientation (amber), height (green).