Domain: Engineering — Structural Engineering
Target concept: Vibration table tests were conducted on short and rigid building models and tall and flexible building models under the same conditions: the short and rigid model exhibited small vibrations and remained almost stationary, while the tall and flexible model showed significant swaying and noticeable deformation.

Video generation prompt: Two building models were placed side by side on the shake table in the laboratory: one was a short and stiff model, and the other was a tall and flexible model. They were subjected to the same horizontal seismic excitation.

Evaluation guide:
(i) Target concept: Dynamic amplification in flexible structures under resonant-horizontal ground motion.
Minimum mechanism: Two structures with differing mass distribution and lateral stiffness must be subjected to identical base excitation; differential response arises solely from modal characteristics, not external forces, damping differences, or modeling errors.
(ii)Storyline: [0s] Static wide shot: two distinct building models (clearly contrasting height and proportions) placed adjacent on labeled shake table, no motion. → [1–3s] Table initiates smooth left-right horizontal oscillation; both models begin moving simultaneously. → [4–7s] Short model moves minimally as a rigid unit (small translation, no bending); tall model exhibits increasing tip displacement and smooth curvature (base stable, top swinging widest). → [8–10s] Motion decays uniformly; both models return to rest without overshoot or residual sway. Perspective: fixed frontal camera, eye-level, full models + table visible, no occlusion.

Manual:
Experimental Procedure
1. Place short rigid building model and tall flexible building model side-by-side on shake table.
2. Activate horizontal sinusoidal excitation at identical amplitude and frequency for both.
Observation of Experimental Phenomena
- Short rigid model remains nearly stationary with minimal lateral movement and no visible deformation.
- Tall flexible model sways significantly with progressive lateral displacement increasing with height and visible bending along its structure.
Summary of Experimental Principles
Structural response to seismic excitation depends on natural period and stiffness: short rigid structures have high natural frequency and resist deformation; tall flexible structures have low natural frequency and amplify lateral motion and interstory drift.

Prompt Grounding rubric:
level_1: No building models appear on a shake table at all: e.g., only one building model is shown, or neither model sits on any vibrating platform, or the two objects shown lack any building-like features (no distinguishable base, walls, or roofline), or the platform never moves and no horizontal shaking is implied anywhere in the clip.
level_2: A short building model and a taller building model both appear on a platform, but they are not placed side by side on one shake table; e.g., one sits on a separate stand, or they are stacked or overlapping; or the two models look nearly the same in height and slenderness so the short-and-stiff versus tall-and-flexible contrast isn't visible; or the platform's motion is vertical or rotational rather than the required left-right horizontal shaking.
level_3: A short, squat building model and a taller, slimmer building model sit side by side on one flat platform that reads clearly as a laboratory shake table; the height and proportion difference between the two models is visually obvious; the platform is still at first and then begins a clear left-right horizontal oscillation that moves both models at the same time.
level_4: The short model and taller model sit side by side on a single shake table with the height/proportion contrast clearly visible, and the platform's left-right horizontal oscillation moves both of them together, as in level 3; in addition, both models stay fully inside the camera frame for the whole clip, the two models keep the same side-by-side spacing on the tabletop throughout without either one sliding toward the other or off to the side, and the shake table's own surface stays flat and rigid as it oscillates, without any warping or buckling.
level_5: Everything described at level 4 holds (clear side-by-side placement, full-frame visibility, stable spacing, and a rigid, flat table surface), and in addition, both models sit squarely on visible mounting footprints or a marked baseplate on the tabletop with no gap beneath either base at the moment shaking begins; no hands, tools, cables, labels, or text overlays ever enter the shot; and the camera holds one static, frontal, eye-level view of both models and the table, with no tilt, pan, zoom, or cut.

Scientific and Causal Correctness rubric:
level_1: The short model and the tall model show the same amount of motion (e.g., both stay nearly still, or both sway heavily), so no structural difference is visible; or the pattern runs backward, with the short model bending or swaying more than the tall one; or neither model's motion visibly tracks with the table's shaking at all.
level_2: The two models clearly move by different amounts, but the taller, more slender one isn't the one swaying more; e.g., the short model sways more than the tall model; or the difference looks arbitrary rather than structural, such as one model spinning while the other only rocks vertically; or one model visibly starts moving before the shake table itself begins to move.
level_3: The short, rigid model shows only a small side-to-side shift and keeps a straight, rectilinear shape with no visible bending; the tall, flexible model shows a clearly larger side-to-side excursion and visible bending along its height; both models' motion starts together when the table begins shaking and stops together when the table stops.
level_4: The short model stays essentially rigid with minimal sway and the tall model bends visibly more, as in level 3; in addition, the short model keeps a straight, upright silhouette throughout, translating as a single rigid block with no twisting or buckling, while the tall model's bending increases smoothly from base to top (its uppermost section swings through a visibly wider arc than its middle, which in turn swings wider than its base) rather than the whole structure simply rocking as one rigid piece.
level_5: The short model stays rigid while the tall model bends with increasing curvature toward its top, as in level 4; in addition, the tall model's top-of-structure excursion is visibly more than double the short model's top excursion at the same instant; the tall model's swaying curve changes smoothly from frame to frame with no sudden kinks or segment-like breaks in its bending profile, consistent with a continuously flexible structure rather than a hinged one; and the short model's motion stays rigid-body throughout, showing no progressive curvature at any height along it.

Spatiotemporal Consistency rubric:
level_1: A severe break in continuity occurs: the short model or the tall model instantly jumps to a different spot on the tabletop between one frame and the next; the shake table itself disappears and reappears; the room's illumination changes abruptly partway through the shaking with no visible cause; or the motion freezes entirely for a stretch of the clip before resuming.
level_2: A noticeable but less severe break occurs: one model's position shifts between frames without a visible path connecting the two positions; the tabletop surface visibly warps or bends as if it were soft while shaking; either model briefly rotates or tips with no connection to the table's own oscillation; or the shadow cast by the tall model swings to the opposite side of its base from one frame to the next even though the room's light hasn't moved and the model's own sway hasn't reversed yet.
level_3: The short model and tall model keep the same side-by-side spacing on the tabletop for the whole clip; the tabletop stays flat and rigid; each model's motion is one continuous path with no jumps, freezes, or skipped frames; and the shadow each model casts onto the tabletop stays roughly beneath that model, sweeping back and forth only in step with the model's own sway rather than jumping to the opposite side or changing brightness on its own.
level_4: Spacing, table rigidity, continuous motion, and matching shadow behavior all hold as in level 3; in addition, neither model's rigid sections stretch, shear, or bend in a way that would be impossible for solid material (only the tall model's designed flexible portion may bend); both models' overall path across the tabletop stays strictly horizontal with no unintended rising or sinking; and each model's base stays touching the tabletop continuously through the entire shaking sequence, never visibly separating from or sliding off the surface mid-motion.
level_5: Everything at level 4 holds: rigid parts stay rigid, motion stays horizontal, and base contact stays unbroken; in addition, the shake table and both models speed up and slow down gradually rather than snapping instantly into or out of motion; the relative sizes and spacing of the two models against the table's edges stay stable under the fixed camera with no parallax drift; and no strobing, ghosting, or motion blur ever obscures whether the tall model's bending is continuous along its height.