Domain: Humanities and Social Sciences — Arts
Target concept: Sketch - One-Point Perspective

Video generation prompt: Display a smooth drawing plane, the artist applies the technique of one-point perspective, drawing a street scene on the plane, strictly following the rule of converging perspective lines.

Evaluation guide:
(i) Target concept: Illusion of three-dimensional depth on a two-dimensional plane using geometric convergence.
Minimum mechanism: A fixed frontal viewpoint, a defined horizon line, and at least two orthogonals that share a single vanishing point, sufficient to trigger human depth-from-perspective inference.
(ii)Storyline: Frame opens on stable frontal view of blank drawing plane → horizon line is drawn horizontally → vanishing point is marked on it → first orthogonal (e.g., left road edge) is drawn from foreground to vanishing point → second orthogonal (e.g., right road edge) is drawn, converging to same point → lateral elements (e.g., building tops) are added, remaining parallel to horizon and aligned to converge toward same point → final frame holds full composition with all convergences visibly intact and vanishing point unambiguously central to the system; no camera movement, no change in viewpoint, no occlusion of key convergence geometry.

Manual:
Experimental Procedure
1. Artist places a blank drawing plane (paper/canvas) in frontal view.
2. Artist draws a straight horizontal line near the top as the horizon line.
3. Artist marks one point on the horizon line as the vanishing point.
4. Artist draws two straight lines from foreground road edges, converging precisely to that vanishing point.
5. Artist adds parallel lateral elements (e.g., building tops, sidewalk edges) aligned horizontally and converging to the same point.
Observation of Experimental Phenomena
A flat drawing plane displays a street receding into depth, where all orthogonal lines (road edges, building fronts) converge to a single vanishing point on a fixed horizon line; no other convergence points appear; surface remains visibly planar and undistorted.
Summary of Experimental Principles
One-point perspective relies on a single vanishing point on the horizon line to create the illusion of depth on a flat plane; all lines perpendicular to the picture plane (orthogonals) must converge there; parallel lines parallel to the picture plane (horizontals and verticals) remain parallel.

Prompt Grounding rubric:
level_1: No street scene, no drawing plane, no converging lines, and no point where lines meet appear anywhere; no artist or drawing action is shown at all.
level_2: A blank drawing surface is shown, but no street elements (road, curbs, buildings) are ever drawn on it, and no lines angle toward a common point.
level_3: A street scene is drawn on the plane with a road and at least one pair of lateral boundaries (curbs or building edges), and at least two straight lines drawn on the plane visibly angle toward each other, but they never visibly meet at one point inside the frame: the meeting point is missing, cut off at the frame's edge, or the lines stop short of it.
level_4: A street scene with road edges plus at least one more set of lines (building tops, a curb line, or a row of lampposts) is drawn, and all of these lines visibly meet at one common point that sits inside the frame; the drawing plane stays flat and stable throughout the sequence.
level_5: Everything required for a 4 holds, and in addition that meeting point sits on a horizontal line drawn near the top of the plane (a horizon line), every converging line traces back to that point as one unbroken segment with no gaps or kinks along the way, and the drawing plane stays perfectly flat with no warping or tilt.

Scientific and Causal Correctness rubric:
level_1: The lines on the plane show no relationship to depth at all: they run parallel, perpendicular, or scattered with no shared heading, so nothing in the drawing suggests the road or buildings receding into the distance.
level_2: The lines appear deliberately placed (e.g., a set of parallel road edges), but at least two of them head in different directions or cross without meeting, so there is no single shared direction the eye can read as 'receding toward one point.'
level_3: Most lines (road edges, building tops) head toward a shared direction, but at least one major line (say, one road edge or a building's roofline) breaks from that heading or stops short before reaching the convergence area, so the sense of recession is only partly convincing.
level_4: Every line that should recede (both road edges, building tops, sidewalk edges) consistently heads toward the same single point, giving an unambiguous sense of the road and buildings receding into depth; no other line (such as a building's side wall or a cross street) cuts across at an angle that would imply a second, contradictory vanishing point.
level_5: All lines fully obey one-point perspective: every orthogonal (road edges, building sides) converges exactly on the one point; every horizontal (building tops, window rows) stays parallel to the horizon with no upward or downward tilt; every vertical (building corners, lamppost poles) stays truly vertical; and repeated elements such as evenly spaced lampposts or windows shrink smoothly as they approach the vanishing point, with no sudden jump in size.

Spatiotemporal Consistency rubric:
level_1: The drawing plane blinks out of frame and comes back moments later; a line snaps from one angle straight to a completely different angle between two frames; the vanishing point jumps to a new spot without any of the converging lines visibly adjusting to follow it; or the plane's lighting flips abruptly between bright and dark with no cause, or parts of the drawing are hidden and revealed inconsistently (occlusion breaks).
level_2: The plane stays visible but visibly warps, bends, or rotates between frames; the convergence point drifts across the frame instead of holding still; or a line appears, disappears, and comes back at a different angle.
level_3: The drawing plane stays flat and in place, the convergence point holds at one fixed spot, and every converging line (the road edges, the building tops) stays on screen continuously from when it is first drawn to the final frame, with no visible jump or stepped motion in how the lines advance.
level_4: Everything required for a 3 holds, and in addition the plane never shifts, the convergence point never moves even slightly, every converging line keeps the same angle and endpoint relative to that point throughout, and there is no shift in lighting or shadow on the plane that would suggest the viewpoint changed.
level_5: Everything required for a 4 holds, and in addition the lines being drawn trace smooth, continuous paths with no visible stepping or double-imaging as they extend across the frame, evenly spaced repeated elements (like lampposts or windows) shrink at a steady, smooth rate as they recede rather than jumping in size, and the horizon line stays level and unmoving from the first frame it appears in to the last.