diff --git a/engine/README.md b/engine/README.md
index 947ffce..e0454d6 100644
--- a/engine/README.md
+++ b/engine/README.md
@@ -83,6 +83,26 @@ It fails for missing/wrong-sized results, nonfinite values, or PSNR below its th
 `test_k.py --chain` remains available for isolated-layer diagnosis; it now selects the first launch consistently and
 fails on dispatch errors rather than continuing with a broken chain.
 
+## Models on the user's machine (install.sh)
+
+A release's `install.sh` builds every model the shim loads, from the user's own DLLs, with
+`d4r/tools/build-engine-models.sh` (`packaging/build_engine_models.sh`; `scripts/stage_engine_kit.sh` puts it and
+d4r's compilers, shaders, the D3D12 harness and glslang into the release):
+
+- Ray Reconstruction needs no capture. `nvngx_dlssd.dll` 310.9.1 holds presets D and E (the kernels and weights of
+  310.7) and F. `engine/rr/build_native_model.sh --dll DLL D|E OUT` and `engine/compile_rr2.py --dll DLL OUT
+  --ptx-dir DIR` take the PTX from the DLL (`kernels/tools/extract_dlss_ptx.py`), the weights as before
+  (`dll_weights.py`, `rr2_pack.py`) and what the capture used to supply from the DLL too: the argument-block
+  constants (`engine/rr/rr_templates.py`, `rr2_templates.py`, which replays the routine that builds NGX's model
+  description), encoder 0's second table of preset F and its arena regions. Built this way, D, E and F are
+  byte-identical to the capture-built models (every file, and `d4r-rr`'s outputs on the reference inputs).
+- Super Resolution weights are packed inside `nvngx_dlss.dll`; they are read where NGX unpacks them. The harness
+  renders one frame per preset (11, 13, 12) through the release's own d4r folder under GE-Proton with
+  `D4R_CUDA_REPLAY_DUMP_DIR` set; `extract_k.py`, `prepare_k.py --lut-only` and `compile_k.py` / `compile_m.py`
+  build K, M and L from that, and `--ldr` their LDR variants from the same frame (NGX's HDR and LDR stages read the
+  same weights). About a minute per preset, ~280 MB of dumps that are deleted afterwards. The results are identical
+  to the models built from full captures.
+
 ## Ordinary frames, without a capture
 
 Create a JSON description with raw linear HDR color, inverse depth, and render-resolution motion vectors:
diff --git a/engine/compile_m.py b/engine/compile_m.py
index 94156b4..b35e38c 100644
--- a/engine/compile_m.py
+++ b/engine/compile_m.py
@@ -50,7 +50,7 @@ def blob_of(directory, ptr_offset=0):
 def main():
     ap = argparse.ArgumentParser(description=__doc__)
     ap.add_argument('capture'); ap.add_argument('output', type=Path); ap.add_argument('--frame', type=int, default=0)
-    ap.add_argument('--ldr', action='store_true', help="NGX's *_ldr_* stages, for games without the HDR flag (capture such a frame)")
+    ap.add_argument('--ldr', action='store_true', help="NGX's *_ldr_* stages, for games without the HDR flag (the weights may come from an HDR capture)")
     ap.add_argument('--hip', type=Path, metavar='KERNEL_DIR', help='also package the network for the native HIP layers: the layer '
                     'weights as NGX uploads them (hipnet.bin) and the rrlite_*_4x4.hsaco kernels of KERNEL_DIR (kernels/build.sh output)')
     a = ap.parse_args()
@@ -60,6 +60,10 @@ def main():
         if len(d) <= a.frame: raise ValueError(f'no launch of {kernel} for frame {a.frame}')
         return d[a.frame]
     R = 'ldr' if a.ldr else 'hdr'
+    # NGX's HDR and LDR stages read the same weights and constants (RE Requiem's m / m-ldr and l / l-ldr packages,
+    # built from separate captures, are identical but for the shaders): an LDR model can come from an HDR capture
+    if a.ldr and not glob.glob(f'{a.capture}/replay/replay-*-rrlite_enc0_4x4_mvlo_ldr*'):
+        R = 'hdr'
     preset_l = bool(glob.glob(f'{a.capture}/replay/replay-*-rrlite_enc0_4x4_mvlo_{R}'))
     if preset_l == bool(glob.glob(f'{a.capture}/replay/replay-*-rrlite_enc0_4x4_mvlo_{R}_folded')):
         raise ValueError(f'the capture must hold the input stage of exactly one of preset M or L ({R})')
diff --git a/engine/prepare_k.py b/engine/prepare_k.py
index a3e0354..087f649 100644
--- a/engine/prepare_k.py
+++ b/engine/prepare_k.py
@@ -2,7 +2,9 @@
 """Prepare a full-frame native K replay from a capture. Does not translate kernels.
 
 prepare_k.py CAPTURE_DIR OUTPUT_DIR [--frames N] [--start FRAME]
-The model's reconstruction tables can be packaged using OUTPUT_DIR/lut.bin.
+prepare_k.py CAPTURE_DIR OUTPUT_DIR --lut-only
+The model's reconstruction tables can be packaged using OUTPUT_DIR/lut.bin. --lut-only writes only that, from the
+first output launch's replay (a capture without the launch dumps: install.sh's weight dump).
 """
 import argparse
 import json
@@ -21,7 +23,15 @@ def main():
     parser.add_argument('output', type=Path)
     parser.add_argument('--frames', type=int, default=0, help='0 = all captured frames')
     parser.add_argument('--start', type=int, default=0)
+    parser.add_argument('--lut-only', action='store_true', help='write only lut.bin')
     a = parser.parse_args()
+    if a.lut_only:
+        outputs = launches(a.capture, OUTPUT)
+        if not outputs:
+            raise ValueError('capture holds no K output launch')
+        a.output.mkdir(parents=True, exist_ok=True)
+        (a.output / 'lut.bin').write_bytes(outputs[0].allocation(280, 16 * 32768))
+        return
     inputs, outputs = launches(a.capture, INPUT), launches(a.capture, OUTPUT)
     if not inputs or not outputs or len(outputs) > len(inputs):
         raise ValueError('capture must contain complete K input/output frame pairs')