Lystrosaurus in motion.

01Prompt

Create a single photorealistic, scientifically grounded paleoart reconstruction of a living Lystrosaurus murrayi, the Early Triassic dicynodont therapsid (a non-mammalian synapsid, not a dinosaur). This is the anatomy reference and opening frame for a later natural locomotion study, so prioritize believable species anatomy and readable feet over drama.
Full prompt
Use case: scientific-educational.
Create a single photorealistic, scientifically grounded paleoart reconstruction of a living Lystrosaurus murrayi, the Early Triassic dicynodont therapsid (a non-mammalian synapsid, not a dinosaur). This is the anatomy reference and opening frame for a later natural locomotion study, so prioritize believable species anatomy and readable feet over drama.

Subject anatomy: one healthy, well-fleshed, approximately one-metre-long individual with a squat barrel-shaped trunk, very short thick neck, proportionately large deep broad skull, short blunt downturned snout ending in a keratinous cropping beak, fleshy cheeks concealing the temporal skull openings, small laterally positioned eyes, and exactly two modest ivory tusks descending from the upper jaw, one on each side. The near tusk is fully visible; the far tusk is only visible where perspective permits. No other exposed teeth. A small inconspicuous ear opening, no external mammalian ear pinnae. Skin is hairless, muted earthy grey-brown, finely pebbled and dimpled with subtle wrinkles at the joints, not crocodilian armour and not exposed skull contours. Skin texture is informed by fossilized integument; the subdued color is a conservative artistic reconstruction.
Four short, powerful limbs. Forelimbs particularly robust with outward-set elbows and a modest semi-sprawling stance; hindlimbs somewhat more under the trunk but flexed, never a fully upright modern pig or dog stance. Broad grounded five-digit feet with short blunt digging claws, not hooves. Belly carried clear of the floor. Short tapering tail held low and visible behind the rump. No horns, crest, sail, mane, dorsal spikes, fur, feathers or reptilian scutes.

Scene and framing: clean pale neutral-grey cyclorama and matte level studio floor, a believable animal reconstruction photographed at body height, soft broad diffuse lighting and a clear soft contact shadow beneath the feet. Wide 16:9 landscape. Camera fixed, lateral side profile with only a very slight three-quarter offset (about 8 degrees) so all four legs can be distinguished. Animal faces RIGHT, entire body and every extremity in frame, occupies approximately 32 percent of image width, and stands in the LEFT third with substantial empty floor to the right for walking across the screen. Full frame, no inset, no diagram, no labels, no text, no humans, no equipment, no suit yet.
Pose: relaxed natural walking-ready stance, all four feet visibly grounded at subtly staggered positions, weight distributed convincingly, head in line with shoulders. Adult-animal proportions and lifelike tissue volume. Maintain anatomy rather than making it cute or monstrous. Museum-quality realism, crisp natural textures, no cinematic shallow focus hiding the legs.

Reconstruction prompt · Written to specify anatomy, pose and framing for OpenAI ImageGen.

02Creature

Lystrosaurus reconstruction, facing right.
Lystrosaurus reconstruction · OpenAI ImageGen, generated from the prompt above.

03Mocap suit

The same Lystrosaurus wearing a dark suit with reflective markers.
Mocap suit edit · OpenAI ImageGen, editing the reconstruction to add a suit and markers.

04Tracked video

2D surface tracks · Kling v3 Pro via fal; OpenCV tracks the body, tail and visible leg surfaces.

05Mesh + texture

The original Lystrosaurus mesh with its triangle edges visible.
200,000-triangle mesh · Hunyuan 3D 3.1 Pro via fal, from the creature image; wireframe rendered in Blender.
The original base-color texture map, unwrapped into UV islands.
4,096 × 4,096 texture map · Hunyuan 3D 3.1 Pro via fal; base-color atlas extracted unchanged from the model.

06WebGL render

Walk with exaggerated physics · Preserved motion + exaggerated XPBD tissue dynamics; rendered in Three.js/WebGL.

Reference ↑
LOADING 3D
LYSTROSAURUS MURRAYI
Preview of the reconstructed Lystrosaurus murrayi model.

Static model preview · Supplied with the Hunyuan 3D 3.1 Pro via fal output.

Loading the animated model…

Drag to orbit · Scroll to zoom
0.0 / 11.0 s

Generated reference imagery. Anatomy, depth and hidden motion remain inferred.

Video fit checks

Back-motion error: 9.5 → 3.2 px on 29 tracks excluded from fitting. Results ↓

Earlier camera/proportion fit: 74% → 78% silhouette overlap on 184 excluded frames. These overlays predate the back correction.

Silhouette comparison · Camera and body proportions fitted in Python; contours drawn with OpenCV. White: video, amber: fitted, blue: baseline.
Physics comparison · 6.8% less modeled joint work
Balanced start353 J
Less joint work329 J
Joint-work estimates · Absolute joint power integrated over each modeled walk; soft-tissue dynamics are excluded.

Same speed and footfall timing. Assumes a 44.3 kg body, massless legs and fixed cadence. Best sampled posture, not a biological energy optimum.

Calculations ↓Model and solver ↓

Shared technique

ImageGen creates the reference; Kling supplies motion; Hunyuan 3D builds the complete mesh. Tracking guides the skeleton and any cuts needed for articulation. Joints and ground contact constrain the movement; Three.js renders the result.

New studies use natural scenes and markerless tracking, with SAM 3 separating subject from background. The earlier Lystrosaurus suit and Tiktaalik green screen remain as experiments.

This is a reconstruction workflow. Generated video, inferred geometry and assumed material properties cannot establish biological accuracy or physically optimal motion.

Rigging choices
Lystrosaurus · Continuous skin
The skin is continuous across the torso, limbs, neck and tail. Separate rigid body pieces would produce seams and prevent natural skin and belly deformation.
Tiktaalik · Continuous skin
The fish-like trunk, tail and fin membranes form a continuous deformable surface. Fin rays and body bends need their own controls without breaking the skin into rigid pieces.
Dreadnoughtus · Continuous skin
Continuous skin connects the long neck, trunk, tail and limbs. Many vertebral and tissue controls should deform one body surface without mechanical seams.
Basilisk drone · Rigid pieces cut from the mesh
Start with the complete mesh. Cut armor, leg links, pads and equipment at structural joints where they need to move independently, keeping each piece rigid and its attachment intact.
Hunter-killer drone · Skin + rigid attachments
Generate the entire four-arm cyborg as one mesh. Keep the living torso continuous; cut the four armored insect-like arms, pincer segments, rotor outriggers, ducts and gun housings at their mechanical joints during rigging.
Cheetah · Continuous skin
A continuous spotted surface bends at joints, with structural supports for the rib cage, pelvis, skull and limb cores.

Generate the whole mesh first. Keep skin continuous; cut rigid pieces where joints require separate movement. Mesh pieces never limit skeleton detail.

Catches + fixes

Hidden motion and missing depth
Overlapping limbs can confuse tracking, and one view cannot reveal depth. Uncertain observations are filtered out; hidden limbs are reconstructed from the visible motion. Those inferred poses remain distinct from observed tracks.
Different bodies need different constraints
Each rig preserves segment lengths and adapts support to its body. The Basilisk drone gives every supported motion group its own control and keeps its metal parts rigid. Repeatable motion adds controls. Basilisk’s paired limbs share dimensions and attachments; body controls follow its long axis. Offsets from that axis require an explicit reason tied to the reference.
Snapping joints and uneven steps
Dreadnoughtus’s knees and elbows flipped bend direction during a stride. Stable bend directions, slight rear-knee flexion, smooth foot lift and landing, and a continuous final partial step corrected those jumps.
Secondary motion needs separate treatment
Damped inertia adds lag to bellies, tails, long necks, fin rays and mounted equipment. It responds to the fitted movement while preserving the primary gait; the physics toggle reveals the added motion.