> For the complete documentation index, see [llms.txt](https://docs.projectsim.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.projectsim.ai/creating-assets/parameters.md). # Parameters Standard, Measured, and High-fidelity accept optional `params` to control mesh, texture, and physics settings. High-fidelity also supports `params.variation`. Each API reference page shows only the options relevant to that endpoint. Procedural accepts the same `params` shape, but only `physics.body` and `physics.articulated` steer its generation; mesh, texture, and variation settings are managed by its pipeline. Omit `params` or individual fields to use defaults; the resolved values are recorded in `effective_params`. ## `mesh` ### `mesh.quality` Controls mesh density (the polygon budget). The pipeline reconstructs at high detail and then decimates down to the tier you pick; topology is always triangles. There's no tier above `standard` — `quality` only reduces from there. | Options | Notes | | ---------------------- | --------------------------------------------------------------------------------------------- | | `standard` *(default)* | Full delivered detail. Choose for hero or close-up assets, or when polycount isn't a concern. | | `low` | Fewer polygons. Choose when placing many assets in a scene, or to lighten runtime/sim cost. | | `ultra_low` | Minimum polygons. Choose for background or distractor objects, or a strict real-time budget. | ## `texture` ### `texture.resolution` Higher resolution means sharper close-ups but larger files and more GPU memory. | Options | Notes | | ----------------------- | ---------------------------------------------------------------------------------------- | | `1024` (1K) | Smallest maps. Choose for many or background assets; minimal VRAM/file size. | | `2048` (2K) | Light. Choose for mid-distance assets. | | `4096` (4K) *(default)* | Sharp at normal distance. A good general default. | | `8192` (8K) | Highest detail. Choose for hero assets seen close up, when you can afford the size/VRAM. | ## `physics` The sim-ready block. Its fields are validated together before any expensive work runs — an unsupported combination is a `422` that lists valid choices. The simulator output formats and collision choices below apply to Standard, Measured, and High-fidelity. Procedural currently exports rigid-body USD with its own collision construction; its accepted `simulator` and `collision` values do not yet change that output. ### `physics.simulator` The target runtime. **It also determines the native output format** — you don't request a format directly. One simulator per request; for a second runtime, send a second request. | Options | Notes | | ----------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------- | | `isaac_sim_physx` *(default)* | Native output: **USD**. NVIDIA Isaac Sim on the PhysX engine — the general-purpose default. | | `isaac_sim_newton` | Native output: **USD**. Isaac Sim on the Newton engine. | | `mujoco` | Native output: **MJCF**. MuJoCo. Rigid bodies only. | | `sapien` | Native output: **URDF**. SAPIEN. Rigid bodies only. | | `genesis` | Native output: **USD**. Genesis. | | `agnostic` | Native output: **FBX + GLB + physics sidecar (JSON)**. Choose for Unreal, Unity, a custom engine, or any portable output. Rigid bodies only. | ### `physics.body` Body behavior lives at **`params.physics.body`** on every create endpoint. Standard, Measured, and High-fidelity support both values below; Procedural supports only `rigid`. Variation sets no longer accept a top-level `body` field — sending one is a `422`. | Options | Notes | | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ | | `rigid` *(default)* | Bodies preserve their shape; skips deformable authoring. Choose for most props. | | `deformable` | Soft-body / FEM authoring. Choose for cloth, foam and other soft objects. Isaac (PhysX/Newton) and Genesis only, and requires `collision: auto`. | ### `physics.collision` The collision shape the simulator uses for contact — separate from the visual mesh. | Options | Notes | | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- | | `auto` *(default)* | The server picks a reasonable shape. Choose when unsure, or when you need `deformable` (which requires `auto`). | | `convex_hull` | One convex shell around the object. Cheapest convex option; fills concavities (a mug becomes solid). Choose for roughly convex objects. | | `convex_decomposition` | Several convex pieces approximating the shape. Choose when concave features matter — handles, openings, recesses. | | `coacd` | Collision-aware convex decomposition; cleaner, more faithful splits. Choose for complex concave geometry where plain decomposition is too coarse. | | `bounding_box` | A single oriented box. Cheapest and least accurate. Choose for boxes, pallets, totes, or coarse background collision. | | `sdf` | Signed-distance field; the most accurate contact. Choose for precise, contact-rich sims. Isaac PhysX/Newton only. | ## `variation` — high-fidelity sets only Steers the image generator on a [high-fidelity set](/creating-assets/high-fidelity-variation-set.md); ignored everywhere else. Define the subject with `seed.images`, `seed.text`, or both. Optional `seed.variation_references` (up to 8 images) provide style, palette, or detail cues alongside any of those input combinations; they belong under `seed`. ### `variation.variation_type` | Options | Notes | | --------------------- | --------------------------------------------------------------------------------------------------------- | | `general` *(default)* | Varies shape and appearance. Choose when you want genuinely different variants. | | `texture` | Varies surface only — never shape or size. Choose for consistent geometry with material/colour diversity. | ### `variation.wildness` | Options | Notes | | ---------------------- | ------------------------------------------------------ | | `subtle` | Small departures from the reference — near-duplicates. | | `moderate` *(default)* | Balanced diversity. | | `bold` | Strong departures. | | `wild` | Maximum diversity. | ## `physics.articulated` — procedural sets only Articulation controls joints separately from body behavior. [Procedural variation sets](/creating-assets/procedural-variation-set.md) use `body: rigid` with one of these choices: | Options | Notes | | ------------------ | --------------------------------------------------------------------------------------- | | `true` *(default)* | Request independently moving rigid parts connected by joints, such as doors or drawers. | | `false` | Request a jointless rigid asset. | Standard, Measured, and High-fidelity produce non-articulated assets and reject this field, even when set to `false`. `articulated` is not a `body` value. To migrate an older procedural request, replace top-level `body: articulated` with `params.physics: {"body": "rigid", "articulated": true}`. For old `body: rigid` requests, use `articulated: false`. For High-fidelity, move the existing `rigid` or `deformable` choice into `params.physics.body`.