Ractr is a physics-native game engine derived from a single scalar field: the same equation renders light, drives gravity, and ticks clocks. License it to build worlds classical engines can't. Invest in the company building both the engine and the first studio shipping on it.
Ractr is built on Density Field Dynamics (DFD) — a unified theory of gravity, optics, and time that passes every laboratory and astronomical test of gravity performed to date, with zero free parameters. Every visual and physical system in the engine is a query against the same field.
A single scalar ψ(x,t) is the refractive index, gravitational potential, and clock rate, simultaneously. Renderer, physics, and time share one GPU buffer. They can't drift out of sync because they literally read the same data.
ψ decays as 1/r outside mass — its analytic far-field works at any scale. A fine-grid simulation bubble follows the player. GPU cost is bounded; world size is not. Planetary-scale MMOs become tractable.
Rays curve through ψ by Fermat's principle. Lensing, redshift, and visible time dilation near mass are emergent, not postprocess. The same equation that matches Einstein's solar-system tests renders your frame.
Modify the density ρ in a region — the field re-relaxes locally over a few frames. No BVH rebuilds, no clipmap refills, no 6-second stalls. Edit cost scales with edit volume, not world size.
The field equation's energy functional is convex. The solver converges monotonically. No warm-starting, no Baumgarte, no constraint stabilization. The math guarantees stability where classical rigid-body stacks fail.
Four quantitative physics gates — far-field decay, light deflection, Kepler orbits, clock dilation — all pass on a 128³ reference grid. Reference implementation runs at interactive framerates on an M3 Pro. Not a demo. Not a whitepaper.
SDF engines were the state of the art for procedural worlds. Ractr supersedes them: same continuous-volume representation, but with real physics instead of a distance metric — and without the performance traps that cripple SDF editing at scale.
We lost 50,000 lines of SDF engine code the hard way, and used it as forcing function. The replacement is smaller, faster where it counts, and physically correct by construction.
DFD posits that the universe is flat three-dimensional space permeated by a single scalar field ψ. Gravity, optical lensing, and time dilation emerge as consequences of two postulates — not independent assumptions stacked together.
It passes every gravitational measurement made to date: solar-system precision tests, binary pulsar timing, LIGO gravitational-wave speeds, EHT black-hole shadows. Zero free parameters once the Hubble constant is measured. Published paper, 208 pages, v3.4 (April 2026).
Because nature is running one field, the most efficient game engine for that universe is the same field — relaxed, sampled, and rendered on a GPU.
If your game or product is blocked by a classical engine's assumptions — triangle meshes, mesh-based collision, baked lighting, chunk-based streaming — Ractr removes the blocker at the substrate level.
Whole-planet worlds at constant per-client GPU cost. No LOD pop. No chunk seams. Fly from surface to orbit without a loading screen.
Destructible worlds where edits propagate causally. No pre-baking. No "destruction mode" as a separate system. Build, dig, collapse — the field reconverges.
Physically correct gravitational phenomena as gameplay: orbit a black hole, feel dilation, watch light bend. The visuals are the physics.
Previz with real optics. Lensing, caustics, and refraction without a separate offline renderer. Same engine for realtime and final pixel.
ρ is a scalar function — model-generatable. Text-to-world becomes a density field, not a mesh export pipeline. AI content plugs in at the substrate.
A reference implementation of a unified gravity theory with verified gates. Useful as a sandbox wherever field theories, gradient-index optics, or large-scale simulation are in scope.
Ractr is source-available under commercial license. Pricing is structured to let studios evaluate, build, and scale without fighting the license.
Source stays private. Licensees get access under NDA. This is the engineering moat, not a GitHub sample.
An AI-powered game development studio built entirely around the Ractr engine. The engine exists for the games. The games exist because the engine finally makes them possible.
Classical engines fight the physics they simulate. Ractr is the physics. Games built on it can do what the classical stack can't: continuous worlds at any scale, gravitational lensing as gameplay, destruction that propagates causally, planet-sized MMOs with bounded per-client compute.
The engine is small enough that a few engineers plus strong AI collaboration can ship worlds a traditional 200-person team would struggle with. Iteration velocity is the competitive advantage; the physics substrate is the unfair advantage.
New Earth — an open-world MMO on a physically realistic planet. Walk across oceans, dig through mountains, watch the sun set into a sea of ray-curved light. Early access for backers once the scalable-world milestone lands.
GPU Jacobi solver. Eikonal raymarcher. All four DFD physics gates pass to < 2% error on a 128³ grid.
Procedural biomes, live solar corona, phase-correct moon, interactive build/destroy, player gravity, real-time raymarched viewer at 30–60 fps on M3 Pro.
ρ becomes a procedural world-wide function. Fine grid follows the player. Analytic far-field handles the exterior. Walk a planet-sized world at constant GPU cost.
Real Earth size. Sun and moon as actual mass sources. Orbital mechanics from the field. Fly from surface to orbit seamlessly.
Server-authoritative ρ world. Each client runs its own bubble. Gravity between players transmitted through the shared far-field.
Classes, combat, tradeskills, quests — built on the Ractr substrate instead of around it.
The engineering journey, one session at a time. One post per build session — that's the rhythm.
Procedural continents, real solar corona, moon phases derived from geometry, and interactive build/destroy that reconverges ψ locally instead of rebuilding the world. The first thing that feels like a game.
Read →Before rendering anything pretty, we verified Ractr by computing four quantitative predictions of DFD directly from the scalar field. Far-field decay, light deflection, Kepler orbits, gravitational time dilation — all matched to analytic values on a 128³ grid.
Read →Why a single scalar ψ(x,t) can replace the triangle mesh, the physics engine, the lightmap, and the voxel grid of a classical game engine — and what makes it simultaneously simpler and more correct.
Read →I had an SDF-based MMO engine nine months in the making. A cleanup command took it out. I tried to recover it. I couldn't. I ended up building something radically better from a physics paper.
Read →We're raising to accelerate the engine roadmap and ship the first AAA-quality world on a physics-native substrate. Accredited investors, $50K minimum.
Every decade a new substrate redefines gaming. Meshes + rasterization (1996). Programmable shaders (2002). Physically based rendering (2014). The next substrate is a physics-native field. Ractr ships it first.
Density Field Dynamics is a published unified theory with zero free parameters, derived by the founder. Competitors would need to derive or license the same theory to match capability. This is defensible at the physics layer, not just the code layer.
Two lines — engine licensing (AAA, simulation, research, defense) and studio game revenue (MMO, live service). Licensing cash-flows first; studio compounds.
Engine verified on four physics gates. Playable planet prototype. Public devlog. Paper v3.4. Reference implementation running in Rust on wgpu across Metal/Vulkan/DX12.
Accredited investors only · Minimum $50K · Current round open