diff --git a/Cargo.lock b/Cargo.lock
index 62085c6..ccded1f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -134,9 +134,9 @@ checksum = "677d306121baf53310a3fd342d88dc0824f6bbeace68347593658525565abee8"
 
 [[package]]
 name = "autocfg"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
 [[package]]
 name = "base-x"
@@ -449,15 +449,26 @@ dependencies = [
 
 [[package]]
 name = "bevy_polyline"
-version = "0.1.3"
+version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c5c82e6ea20642e4d8aa120bcf0ae09d7cae067825d7f954228c246bb8c948b"
+checksum = "0973d599ae862049333b74cb5216de1be07cf7db675b6dcc0e055006ab41be26"
 dependencies = [
  "bevy",
  "bitflags",
  "naga",
 ]
 
+[[package]]
+name = "bevy_rapier3d"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5186c735d7aa202e982f93c71b444d34bf15fed44aca942f9b5f2940e3d06764"
+dependencies = [
+ "bevy",
+ "nalgebra",
+ "rapier3d",
+]
+
 [[package]]
 name = "bevy_reflect"
 version = "0.6.0"
@@ -804,7 +815,7 @@ dependencies = [
  "bitflags",
  "block",
  "cocoa-foundation",
- "core-foundation 0.9.2",
+ "core-foundation 0.9.3",
  "core-graphics 0.22.3",
  "foreign-types",
  "libc",
@@ -819,7 +830,7 @@ checksum = "7ade49b65d560ca58c403a479bb396592b155c0185eada742ee323d1d68d6318"
 dependencies = [
  "bitflags",
  "block",
- "core-foundation 0.9.2",
+ "core-foundation 0.9.3",
  "core-graphics-types",
  "foreign-types",
  "libc",
@@ -889,9 +900,9 @@ dependencies = [
 
 [[package]]
 name = "core-foundation"
-version = "0.9.2"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6888e10551bb93e424d8df1d07f1a8b4fceb0001a3a4b048bfc47554946f47b3"
+checksum = "194a7a9e6de53fa55116934067c844d9d749312f75c6f6d0980e8c252f8c2146"
 dependencies = [
  "core-foundation-sys 0.8.3",
  "libc",
@@ -934,7 +945,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2581bbab3b8ffc6fcbd550bf46c355135d16e9ff2a6ea032ad6b9bf1d7efe4fb"
 dependencies = [
  "bitflags",
- "core-foundation 0.9.2",
+ "core-foundation 0.9.3",
  "core-graphics-types",
  "foreign-types",
  "libc",
@@ -947,7 +958,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a68b68b3446082644c91ac778bf50cd4104bfb002b5a6a7c44cca5a2c70788b"
 dependencies = [
  "bitflags",
- "core-foundation 0.9.2",
+ "core-foundation 0.9.3",
  "foreign-types",
  "libc",
 ]
@@ -967,9 +978,9 @@ dependencies = [
 
 [[package]]
 name = "crc32fast"
-version = "1.3.1"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2209c310e29876f7f0b2721e7e26b84aff178aa3da5d091f9bfbf47669e60e3"
+checksum = "b540bd8bc810d3885c6ea91e2018302f68baba2129ab3e88f32389ee9370880d"
 dependencies = [
  "cfg-if 1.0.0",
 ]
@@ -1011,9 +1022,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.6"
+version = "0.9.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97242a70df9b89a65d0b6df3c4bf5b9ce03c5b7309019777fbde37e7537f8762"
+checksum = "c00d6d2ea26e8b151d99093005cb442fb9a37aeaca582a03ec70946f49ab5ed9"
 dependencies = [
  "cfg-if 1.0.0",
  "crossbeam-utils",
@@ -1024,9 +1035,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-queue"
-version = "0.3.3"
+version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b979d76c9fcb84dffc80a73f7290da0f83e4c95773494674cb44b76d13a7a110"
+checksum = "4dd435b205a4842da59efd07628f921c096bc1cc0a156835b4fa0bcb9a19bcce"
 dependencies = [
  "cfg-if 1.0.0",
  "crossbeam-utils",
@@ -1034,9 +1045,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.6"
+version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfcae03edb34f947e64acdb1c33ec169824e20657e9ecb61cef6c8c74dcb8120"
+checksum = "b5e5bed1f1c269533fa816a0a5492b3545209a205ca1a54842be180eb63a16a6"
 dependencies = [
  "cfg-if 1.0.0",
  "lazy_static",
@@ -1054,7 +1065,7 @@ version = "0.1.0"
 dependencies = [
  "bevy",
  "bevy_polyline",
- "heron",
+ "bevy_rapier3d",
  "rand",
 ]
 
@@ -1132,16 +1143,6 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ea835d29036a4087793836fa931b08837ad5e957da9e23886b29586fb9b6650"
 
-[[package]]
-name = "duplicate"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3cdaf23abc9bcc47fda1ae3af68425a22b4dfbd745f9077be0eaad5320f75f52"
-dependencies = [
- "heck",
- "proc-macro-error",
-]
-
 [[package]]
 name = "either"
 version = "1.6.1"
@@ -1220,15 +1221,15 @@ checksum = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
 
 [[package]]
 name = "futures-core"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0c8ff0461b82559810cdccfde3215c3f373807f5e5232b71479bff7bb2583d7"
+checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
 
 [[package]]
 name = "futures-io"
-version = "0.3.19"
+version = "0.3.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b1f9d34af5a1aac6fb380f735fe510746c38067c5bf16c7fd250280503c971b2"
+checksum = "fc4045962a5a5e935ee2fdedaa4e08284547402885ab326734432bed5d12966b"
 
 [[package]]
 name = "futures-lite"
@@ -1428,15 +1429,6 @@ dependencies = [
  "ahash",
 ]
 
-[[package]]
-name = "heck"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "87cbf45460356b7deeb5e3415b5563308c0a9b057c85e12b06ad551f98d0a6ac"
-dependencies = [
- "unicode-segmentation",
-]
-
 [[package]]
 name = "hermit-abi"
 version = "0.1.19"
@@ -1446,54 +1438,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "heron"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54579e36436e33827e21f046ea6752b3a93dbd0b05884bffe982568af7b3bebd"
-dependencies = [
- "bevy",
- "cfg_aliases",
- "heron_core",
- "heron_macros",
- "heron_rapier",
-]
-
-[[package]]
-name = "heron_core"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7099a07736abf70026b1e474fff8d74a8fa88a834cfd33e974541e6b056abb41"
-dependencies = [
- "bevy",
- "cfg_aliases",
- "duplicate",
-]
-
-[[package]]
-name = "heron_macros"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a09c1e02655f04faf8d6b485f6c27422f3769343c30c39e51a2cd25f3f2869c3"
-dependencies = [
- "quote",
- "syn",
-]
-
-[[package]]
-name = "heron_rapier"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4bf94fface67dce71dfd0ab2c0a8b211cacf7b1d02532669671892350765b340"
-dependencies = [
- "bevy",
- "cfg_aliases",
- "crossbeam",
- "fnv",
- "heron_core",
- "rapier3d",
-]
-
 [[package]]
 name = "hex"
 version = "0.4.3"
@@ -1621,9 +1565,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.114"
+version = "0.2.117"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0005d08a8f7b65fb8073cb697aa0b12b631ed251ce73d862ce50eeb52ce3b50"
+checksum = "e74d72e0f9b65b5b4ca49a346af3976df0f9c61d550727f349ecd559f251a26c"
 
 [[package]]
 name = "libloading"
@@ -1641,6 +1585,12 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7fc7aa29613bd6a620df431842069224d8bc9011086b1db4c0e0cd47fa03ec9a"
 
+[[package]]
+name = "libm"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33a33a362ce288760ec6a508b94caaec573ae7d3bbbd91b87aa0bad4456839db"
+
 [[package]]
 name = "libudev-sys"
 version = "0.1.4"
@@ -1653,9 +1603,9 @@ dependencies = [
 
 [[package]]
 name = "lock_api"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "712a4d093c9976e24e7dbca41db895dabcbac38eb5f4045393d17a95bdfb1109"
+checksum = "88943dd7ef4a2e5a4bfa2753aaab3013e34ce2533d1996fb18ef591e315e2b3b"
 dependencies = [
  "scopeguard",
 ]
@@ -1745,9 +1695,9 @@ dependencies = [
 
 [[package]]
 name = "mint"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "162e591484b4b8fe9e1ca16ebf07ab584fdc3334508d76a788cd54d89cfc20dc"
+checksum = "e53debba6bda7a793e5f99b8dacf19e626084f525f7829104ba9898f367d85ff"
 
 [[package]]
 name = "mio"
@@ -1793,11 +1743,12 @@ dependencies = [
 
 [[package]]
 name = "nalgebra"
-version = "0.29.0"
+version = "0.30.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d506eb7e08d6329505faa8a3a00a5dcc6de9f76e0c77e4b75763ae3c770831ff"
+checksum = "4fb2d0de08694bed883320212c18ee3008576bfe8c306f4c3c4a58b4876998be"
 dependencies = [
  "approx",
+ "glam",
  "matrixmultiply",
  "nalgebra-macros",
  "num-complex",
@@ -1957,6 +1908,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
 dependencies = [
  "autocfg",
+ "libm 0.2.2",
 ]
 
 [[package]]
@@ -2024,6 +1976,16 @@ dependencies = [
  "ttf-parser",
 ]
 
+[[package]]
+name = "packed_simd_2"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "defdcfef86dcc44ad208f71d9ff4ce28df6537a4e0d6b0e8e845cb8ca10059a6"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libm 0.1.4",
+]
+
 [[package]]
 name = "parking"
 version = "2.0.0"
@@ -2057,9 +2019,9 @@ dependencies = [
 
 [[package]]
 name = "parry3d"
-version = "0.7.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "067fa44bf7f7cc4022756ef9796c5f8d67c7a63041df71e6eeb09ad08ab1ece8"
+checksum = "c418a03e2ba297c931c530a690b305ce3b3dcc675caf16777f4f8565c8e84732"
 dependencies = [
  "approx",
  "bitflags",
@@ -2145,30 +2107,6 @@ dependencies = [
  "toml",
 ]
 
-[[package]]
-name = "proc-macro-error"
-version = "1.0.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
-dependencies = [
- "proc-macro-error-attr",
- "proc-macro2",
- "quote",
- "syn",
- "version_check",
-]
-
-[[package]]
-name = "proc-macro-error-attr"
-version = "1.0.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
-dependencies = [
- "proc-macro2",
- "quote",
- "version_check",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.36"
@@ -2241,9 +2179,9 @@ checksum = "63e935c45e09cc6dcf00d2f0b2d630a58f4095320223d47fc68918722f0538b6"
 
 [[package]]
 name = "rapier3d"
-version = "0.11.1"
+version = "0.12.0-alpha.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfc8dde2352efdbc0813938fcc41d12651b4bb05211e81d2b44ff6c09d39b2ac"
+checksum = "3f0590e74514004c7313934d092ed071302146323124efde9d30d6aa517186bf"
 dependencies = [
  "approx",
  "arrayvec",
@@ -2256,8 +2194,10 @@ dependencies = [
  "num-derive",
  "num-traits",
  "parry3d",
+ "rayon",
  "rustc-hash",
  "simba",
+ "vec_map",
 ]
 
 [[package]]
@@ -2275,6 +2215,31 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "60a357793950651c4ed0f3f52338f53b2f809f32d83a07f72909fa13e4c6c1e3"
 
+[[package]]
+name = "rayon"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c06aca804d41dbc8ba42dfd964f0d01334eceb64314b9ecf7c5fad5188a06d90"
+dependencies = [
+ "autocfg",
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d78120e2c850279833f1dd3582f730c4ab53ed95aeaaaa862a2a5c71b1656d8e"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "lazy_static",
+ "num_cpus",
+]
+
 [[package]]
 name = "rectangle-pack"
 version = "0.4.2"
@@ -2458,13 +2423,14 @@ dependencies = [
 
 [[package]]
 name = "simba"
-version = "0.6.0"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0b7840f121a46d63066ee7a99fc81dcabbc6105e437cae43528cea199b5a05f"
+checksum = "13a2609e876d4f77f6ab7ff5254fc39b4f1927ba8e6db3d18be7c32534d3725e"
 dependencies = [
  "approx",
  "num-complex",
  "num-traits",
+ "packed_simd_2",
  "paste",
  "wide",
 ]
@@ -2561,7 +2527,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b0dc6d20ce137f302edf90f9cd3d278866fd7fb139efca6f246161222ad6d87"
 dependencies = [
  "lazy_static",
- "libm",
+ "libm 0.1.4",
 ]
 
 [[package]]
@@ -2637,9 +2603,9 @@ dependencies = [
 
 [[package]]
 name = "tracing"
-version = "0.1.29"
+version = "0.1.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "375a639232caf30edfc78e8d89b2d4c375515393e7af7e16f01cd96917fb2105"
+checksum = "2d8d93354fe2a8e50d5953f5ae2e47a3fc2ef03292e7ea46e3cc38f549525fb9"
 dependencies = [
  "cfg-if 1.0.0",
  "pin-project-lite",
@@ -2649,9 +2615,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-attributes"
-version = "0.1.18"
+version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f4f480b8f81512e825f337ad51e94c1eb5d3bbdf2b363dcd01e2b19a9ffe3f8e"
+checksum = "8276d9a4a3a558d7b7ad5303ad50b53d58264641b82914b7ada36bd762e7a716"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2660,11 +2626,12 @@ dependencies = [
 
 [[package]]
 name = "tracing-core"
-version = "0.1.21"
+version = "0.1.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f4ed65637b8390770814083d20756f87bfa2c21bf2f110babdc5438351746e4"
+checksum = "03cfcb51380632a72d3111cb8d3447a8d908e577d31beeac006f836383d29a23"
 dependencies = [
  "lazy_static",
+ "valuable",
 ]
 
 [[package]]
@@ -2680,9 +2647,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-subscriber"
-version = "0.3.7"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5312f325fe3588e277415f5a6cca1f4ccad0f248c4cd5a4bd33032d7286abc22"
+checksum = "74786ce43333fcf51efe947aed9718fbe46d5c7328ec3f1029e818083966d9aa"
 dependencies = [
  "ansi_term",
  "lazy_static",
@@ -2719,12 +2686,6 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dcf81ac59edc17cc8697ff311e8f5ef2d99fcbd9817b34cec66f90b6c3dfd987"
 
-[[package]]
-name = "unicode-segmentation"
-version = "1.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8895849a949e7845e06bd6dc1aa51731a103c42707010a5b591c0038fb73385b"
-
 [[package]]
 name = "unicode-width"
 version = "0.1.9"
@@ -2747,6 +2708,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "vec_map"
 version = "0.8.2"
@@ -2987,7 +2954,7 @@ checksum = "9b43cc931d58b99461188607efd7acb2a093e65fc621f54cad78517a6063e73a"
 dependencies = [
  "bitflags",
  "cocoa",
- "core-foundation 0.9.2",
+ "core-foundation 0.9.3",
  "core-graphics 0.22.3",
  "core-video-sys",
  "dispatch",
diff --git a/Cargo.toml b/Cargo.toml
index bf7330a..85fd106 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,9 +19,9 @@ features = [
   "x11",
 ]
 
-[dependencies.heron]
-version = "1.1"
-features = ["3d"]
+[dependencies.bevy_rapier3d]
+version = "0.12"
+features = ["parallel", "simd-nightly"]
 
 # Enable optimizations for dependencies (incl. Bevy), but not for our code:
 [profile.dev.package."*"]
diff --git a/src/action.rs b/src/action.rs
index c38edca..f05a345 100644
--- a/src/action.rs
+++ b/src/action.rs
@@ -1,14 +1,15 @@
 use bevy::prelude::*;
-use heron::prelude::*;
+use bevy_rapier3d::{na::Vector3, prelude::*};
 
-use crate::{geometry::CyberBike, input::InputState};
+use crate::{
+    geometry::{CyberBike, CyberSphere, PLANET_RADIUS},
+    input::InputState,
+};
 
 /// Mouse sensitivity and movement speed
 pub struct MovementSettings {
     pub sensitivity: f32,
     pub accel: f32,
-    pub drag: f32,
-    pub gravity: f32,
 }
 
 impl Default for MovementSettings {
@@ -16,151 +17,119 @@ impl Default for MovementSettings {
         Self {
             sensitivity: 1.0,
             accel: 40.,
-            drag: 0.0005,
-            gravity: 10.0,
         }
     }
 }
 
-#[derive(Component, Default)]
-pub(crate) struct CyberBikeState {
-    pub velocity: Vec3,
-    pub colliding: bool,
+fn setup_colliders(
+    mut commands: Commands,
+    planet_query: Query<Entity, With<CyberSphere>>,
+    bike_query: Query<(Entity, &Transform), With<CyberBike>>,
+) {
+    let planet = planet_query.single();
+    let pbody = RigidBodyBundle {
+        body_type: RigidBodyType::Static.into(),
+        ..Default::default()
+    };
+    let pcollide = ColliderBundle {
+        shape: ColliderShape::ball(PLANET_RADIUS).into(),
+        material: ColliderMaterial {
+            friction: 0.0,
+            restitution: 0.3,
+            ..Default::default()
+        }
+        .into(),
+        ..Default::default()
+    };
+    commands
+        .entity(planet)
+        .insert_bundle(pbody)
+        .insert_bundle(pcollide);
+
+    let (bike, xform) = bike_query.single();
+    let mut bbody = RigidBodyBundle::default();
+    bbody.damping.angular_damping = 0.8;
+    bbody.damping.linear_damping = 0.5;
+    let isometry = Isometry::from_parts(xform.translation.into(), xform.rotation.into());
+    bbody.position = isometry.into();
+    // collider
+    let shape = ColliderShape::capsule(
+        Vec3::new(0.0, 0.0, -1.25).into(),
+        Vec3::new(0.0, 0.0, 1.2).into(),
+        0.4,
+    );
+    let bcollide = ColliderBundle {
+        shape: shape.into(),
+        mass_properties: ColliderMassProps::Density(0.3).into(),
+        material: ColliderMaterial {
+            friction: 0.0,
+            restitution: 0.3,
+            ..Default::default()
+        }
+        .into(),
+        ..Default::default()
+    };
+    commands
+        .entity(bike)
+        .insert_bundle(bbody)
+        .insert_bundle(bcollide)
+        .insert(ColliderPositionSync::Discrete);
 }
 
-fn falling_cat(time: Res<Time>, mut bike_query: Query<&mut Transform, With<CyberBike>>) {
-    let dt = time.delta_seconds();
+fn gravity(xform: Query<&Transform, With<CyberBike>>, mut config: ResMut<RapierConfiguration>) {
+    let gravity = xform.single().translation.normalize() * -8.0;
+    config.gravity = gravity.into();
+}
 
-    let mut bike_xform = bike_query.single_mut();
+fn falling_cat(
+    mut bike_query: Query<(&Transform, &mut RigidBodyForcesComponent), With<CyberBike>>,
+) {
+    let (bike_xform, mut forces) = bike_query.single_mut();
     let up = bike_xform.translation.normalize();
     let cam_up = bike_xform.up();
     let cos = up.dot(cam_up);
 
     let theta = cos.acos();
-    let rate = if !theta.is_normal() {
-        0.0
-    } else if theta.is_sign_negative() {
-        -0.4
-    } else {
-        0.4
-    } * dt;
-    let angle = if rate.is_sign_negative() {
-        rate.max(theta)
-    } else {
-        rate.min(theta)
-    };
+    let force_mag = if !theta.is_normal() { 0.0 } else { theta * 5.0 };
+    let torque = cam_up.cross(up).normalize() * force_mag;
 
-    let rot = Quat::from_axis_angle(cam_up.cross(up).normalize(), angle);
-
-    if rot.is_finite() && theta.abs() > 1.0f32.to_radians() {
-        bike_xform.rotate(rot);
-    }
+    forces.torque = torque.into();
 }
 
-fn update_velocity(
-    time: Res<Time>,
+fn update_forces(
     settings: Res<MovementSettings>,
     input: Res<InputState>,
-    mut query: Query<(&Transform, &mut CyberBikeState)>,
+    mut query: Query<
+        (
+            &Transform,
+            &mut RigidBodyForcesComponent,
+            &mut ColliderMaterialComponent,
+        ),
+        With<CyberBike>,
+    >,
 ) {
-    let dt = time.delta_seconds();
-    let (xform, mut state) = query.single_mut();
+    let (xform, mut forces, mut cmat) = query.single_mut();
 
-    // first gravity
-    let down = -xform.translation.normalize();
-    let dvel = down * settings.gravity * dt;
-    let mut vel = if state.velocity.is_finite() {
-        state.velocity + dvel
-    } else {
-        dvel
-    };
-
-    // thrust or brake
-    vel += xform.forward() * input.throttle * dt * settings.accel;
+    // thrust
+    let thrust: Vector3<f32> = (xform.forward() * input.throttle * settings.accel).into();
+    forces.force += thrust;
 
     // brake
-    if input.brake {
-        let s = vel.length_squared();
-        if s < 0.05 {
-            vel = Vec3::ZERO;
-        } else {
-            vel -= vel.normalize() * settings.accel * dt;
-        }
-    }
+    cmat.friction = if input.brake { 2.0 } else { 0.0 };
 
-    // drag
-    let v2 = vel.length_squared().min(100_000.0);
-    let drag = vel * settings.drag * v2 * dt;
-    vel -= drag;
-
-    if vel.length_squared() < 0.0001 {
-        vel = Vec3::ZERO;
-    }
-
-    state.velocity = vel;
+    // steering
+    let torque: Vector3<f32> = (xform.up() * input.yaw * settings.sensitivity).into();
+    forces.torque += torque;
 }
 
-fn apply_velocity(time: Res<Time>, mut bike_query: Query<(&mut Transform, &CyberBikeState)>) {
-    let dt = time.delta_seconds();
-
-    let (mut bike_xform, state) = bike_query.single_mut();
-
-    if state.velocity.is_finite() {
-        bike_xform.translation += state.velocity * dt;
-    }
-}
-
-fn steer_cyberbike(
-    settings: Res<MovementSettings>,
-    windows: Res<Windows>,
-    time: Res<Time>,
-    istate: Res<InputState>,
-    mut query: Query<&mut Transform, With<CyberBike>>,
-) {
-    let window = windows.get_primary().unwrap();
-    let window_scale = window.height().min(window.width());
-    let dt = time.delta_seconds();
-    let mut transform = query.single_mut();
-
-    let d_yaw = (settings.sensitivity * dt * window_scale * istate.yaw).to_radians();
-    let rotation = Quat::from_axis_angle(transform.local_y(), d_yaw);
-
-    transform.rotate(rotation);
-}
-
-fn collisions(
-    mut events: EventReader<CollisionEvent>,
-    mut query: Query<(&Transform, &mut CyberBikeState)>,
-) {
-    let (xform, mut state) = query.single_mut();
-
-    for event in events.iter() {
-        if let CollisionEvent::Started(_, _) = event {
-            state.colliding = true;
-        } else {
-            state.colliding = false;
-        }
-    }
-
-    // now see if we're currently colliding
-    if state.colliding {
-        let down = -xform.translation.normalize();
-        let vel = state.velocity;
-        let dvel = down * vel.dot(down);
-        state.velocity -= dvel;
-    }
-}
-
-pub struct CyberPhysicsPlugin;
-impl Plugin for CyberPhysicsPlugin {
+pub struct CyberActionPlugin;
+impl Plugin for CyberActionPlugin {
     fn build(&self, app: &mut App) {
-        app.init_resource::<CyberBikeState>()
-            .init_resource::<MovementSettings>()
-            .add_plugin(PhysicsPlugin::default())
-            .add_system(collisions)
+        app.init_resource::<MovementSettings>()
+            .add_plugin(RapierPhysicsPlugin::<NoUserData>::default())
+            .add_startup_system_to_stage(StartupStage::PostStartup, setup_colliders)
+            .add_system(gravity)
             .add_system(falling_cat)
-            .add_system(update_velocity)
-            .add_system(steer_cyberbike)
-            .add_system(apply_velocity);
+            .add_system(update_forces);
     }
 }
diff --git a/src/geometry.rs b/src/geometry.rs
index f4b207f..b67a688 100644
--- a/src/geometry.rs
+++ b/src/geometry.rs
@@ -1,5 +1,4 @@
 use bevy::prelude::*;
-use heron::prelude::{CollisionShape, RigidBody};
 
 use crate::Label;
 
@@ -17,6 +16,8 @@ fn spawn_giant_sphere(
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<StandardMaterial>>,
 ) {
+    let mut color = Color::DARK_GRAY;
+    color.set_a(0.0);
     commands
         .spawn_bundle(PbrBundle {
             mesh: meshes.add(Mesh::from(shape::Icosphere {
@@ -24,23 +25,19 @@ fn spawn_giant_sphere(
                 subdivisions: 24,
             })),
             material: materials.add(StandardMaterial {
-                base_color: Color::DARK_GRAY,
+                base_color: color,
                 metallic: 0.6,
                 perceptual_roughness: 0.4,
+                alpha_mode: AlphaMode::Mask(0.5),
                 ..Default::default()
             }),
 
             ..Default::default()
         })
-        .insert(CyberSphere)
-        .insert(RigidBody::Static)
-        .insert(CollisionShape::Sphere {
-            radius: PLANET_RADIUS,
-        });
+        .insert(CyberSphere);
 }
 
 fn spawn_cyberbike(mut commands: Commands, asset_server: Res<AssetServer>) {
-    use crate::action::CyberBikeState;
     commands
         .spawn_bundle((
             Transform {
@@ -53,13 +50,7 @@ fn spawn_cyberbike(mut commands: Commands, asset_server: Res<AssetServer>) {
         .with_children(|rider| {
             rider.spawn_scene(asset_server.load("cyber-bike_no_y_up.glb#Scene0"));
         })
-        .insert(CyberBike)
-        .insert(RigidBody::Dynamic)
-        .insert(CollisionShape::Capsule {
-            half_segment: 2.0,
-            radius: 0.8,
-        })
-        .insert(CyberBikeState::default());
+        .insert(CyberBike);
 }
 
 pub struct CyberGeomPlugin;
diff --git a/src/main.rs b/src/main.rs
index 5f0e67a..5b92e07 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,6 @@
 use bevy::prelude::*;
 use cyber_rider::{
-    action::{CyberPhysicsPlugin, MovementSettings},
+    action::{CyberActionPlugin, MovementSettings},
     camera::CyberCamPlugin,
     disable_mouse_trap,
     geometry::CyberGeomPlugin,
@@ -11,10 +11,8 @@ use cyber_rider::{
 };
 
 const MOVEMENT_SETTINGS: MovementSettings = MovementSettings {
-    sensitivity: 0.3, // default: 1.0
-    accel: 20.0,      // default: 40.0
-    drag: 0.0001,     // default: 0.0005
-    gravity: 10.0,    // default: 10.0
+    sensitivity: 4.0, // default: 1.0
+    accel: 15.0,      // default: 40.0
 };
 
 fn main() {
@@ -24,7 +22,7 @@ fn main() {
         .add_plugin(CyberGeomPlugin)
         .add_plugin(CyberGlamorPlugin)
         .add_plugin(CyberInputPlugin)
-        .add_plugin(CyberPhysicsPlugin)
+        .add_plugin(CyberActionPlugin)
         .insert_resource(MOVEMENT_SETTINGS)
         .add_plugin(CyberCamPlugin)
         .add_plugin(CyberSpaceLightsPlugin)
diff --git a/src/ui.rs b/src/ui.rs
index e0e301e..565b7ce 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -1,6 +1,7 @@
 use bevy::prelude::*;
+use bevy_rapier3d::prelude::*;
 
-use crate::action::CyberBikeState;
+use crate::geometry::CyberBike;
 
 #[derive(Component)]
 struct UpText;
@@ -32,10 +33,13 @@ fn setup_ui(mut commands: Commands, asset_server: Res<AssetServer>) {
         .insert(UpText);
 }
 
-fn update_ui(state_query: Query<&CyberBikeState>, mut text_query: Query<&mut Text, With<UpText>>) {
+fn update_ui(
+    state_query: Query<&RigidBodyVelocityComponent, With<CyberBike>>,
+    mut text_query: Query<&mut Text, With<UpText>>,
+) {
     let mut text = text_query.single_mut();
     let state = state_query.single();
-    text.sections[0].value = format!("spd: {:.2}", state.velocity.length(),);
+    text.sections[0].value = format!("spd: {:.2}", state.linvel.magnitude());
 }
 
 pub struct CyberUIPlugin;