Initial commit: Hermes-Houdini Bridge

- Shelf tool to open/close command port in Houdini - hhb client script (eval, script, get-selected, set-param, etc.) - Hermes skill with standard hou module workflows - Example: create pyro setup - hou module quick reference
2026-07-12 12:14:36 +00:00
commit dd2a1734eb
6 changed files with 621 additions and 0 deletions
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+#!/usr/bin/env bash
+# ──────────────────────────────────────────────────────────
+# hhb — Hermes-Houdini Bridge Client
+# Sends Python/hou commands to a running Houdini session
+# via SSH + hcommand.
+# ──────────────────────────────────────────────────────────
+set -euo pipefail
+
+HOST="${HHB_HOST:-niklas@192.168.178.39}"
+PORT="${HHB_PORT:-12345}"
+HCOMMAND="${HHB_HCOMMAND:-/opt/hfs21.0/bin/hcommand}"
+WORKSPACE="${HHB_WORKSPACE:-/opt/data/projects/hermes-houdini-bridge}"
+
+usage() {
+    cat <<'EOF'
+Usage: hhb <command> [args]
+
+Commands:
+  eval <python_code>     Execute Python code in the running Houdini session.
+                         Example: hhb eval "print(hou.selectedNodes())"
+
+  script <file.py>       Send a Python script file to Houdini and execute it.
+                         Example: hhb script ./examples/create_pyro_setup.py
+
+  get-selected           Print paths and types of selected nodes.
+  get-param <parm>       Get value of a parameter on the first selected node.
+  set-param <parm> <val> Set a parameter on the first selected node.
+  get-inputs             Print input connections of the first selected node.
+  status                 Check if the bridge port is open.
+  help                   Show this help.
+
+EOF
+    exit 0
+}
+
+# ── Helpers ──────────────────────────────────────────────
+
+run_remote_python() {
+    # Write Python code to a temp file, execute via hcommand.
+    # This avoids quoting hell with complex Python snippets.
+    local python_code="$1"
+    local tmpfile="/tmp/hhb_$$.py"
+
+    # Upload script
+    printf '%s' "$python_code" | ssh "$HOST" "cat > $tmpfile"
+
+    # Execute via hscript's python command — reads file and execs
+    local output
+    output=$(ssh "$HOST" \
+        "$HCOMMAND $PORT \"python exec(open('$tmpfile').read())\"" 2>&1) || {
+        local rc=$?
+        ssh "$HOST" "rm -f $tmpfile" 2>/dev/null
+        echo "hhb: hcommand failed (exit $rc)" >&2
+        echo "$output" >&2
+        return $rc
+    }
+
+    # Cleanup
+    ssh "$HOST" "rm -f $tmpfile" 2>/dev/null
+
+    # hcommand output has a prefix line like "-> foobar", strip it
+    echo "$output" | sed 's/^->\s*//'
+}
+
+# ── Commands ──────────────────────────────────────────────
+
+cmd_status() {
+    local output
+    output=$(ssh "$HOST" "$HCOMMAND $PORT openport" 2>&1) || {
+        echo "Bridge INACTIVE — Houdini not reachable or port $PORT closed."
+        return 1
+    }
+    echo "$output" | sed 's/^->\s*//'
+}
+
+cmd_eval() {
+    [[ $# -ge 1 ]] || { echo "Usage: hhb eval <python_code>"; exit 1; }
+    run_remote_python "$*"
+}
+
+cmd_script() {
+    [[ $# -ge 1 ]] || { echo "Usage: hhb script <file.py>"; exit 1; }
+    local script_path="$1"
+    [[ -f "$script_path" ]] || { echo "File not found: $script_path"; exit 1; }
+
+    scp -q "$script_path" "$HOST:/tmp/hhb_script_$$.py"
+    local output
+    output=$(ssh "$HOST" \
+        "$HCOMMAND $PORT \"python exec(open('/tmp/hhb_script_$$.py').read())\"" 2>&1) || {
+        local rc=$?
+        ssh "$HOST" "rm -f /tmp/hhb_script_$$.py" 2>/dev/null
+        echo "hhb: hcommand failed (exit $rc)" >&2
+        echo "$output" >&2
+        return $rc
+    }
+    ssh "$HOST" "rm -f /tmp/hhb_script_$$.py" 2>/dev/null
+    echo "$output" | sed 's/^->\s*//'
+}
+
+cmd_get_selected() {
+    run_remote_python '
+import hou
+nodes = hou.selectedNodes()
+if not nodes:
+    print("No nodes selected.")
+else:
+    for n in nodes:
+        print(f"{n.path():50s}  [{n.type().name()}]")
+'
+}
+
+cmd_get_param() {
+    [[ $# -ge 1 ]] || { echo "Usage: hhb get-param <parm_name>"; exit 1; }
+    local parm="$1"
+    run_remote_python "
+import hou
+nodes = hou.selectedNodes()
+if not nodes:
+    print('No nodes selected.')
+else:
+    p = nodes[0].parm('$parm')
+    if p is None:
+        print(f'Parameter \"$parm\" not found on {nodes[0].path()}')
+    else:
+        print(f'{nodes[0].path()}.{p.name()} = {p.eval()}')
+"
+}
+
+cmd_set_param() {
+    [[ $# -ge 2 ]] || { echo "Usage: hhb set-param <parm_name> <value>"; exit 1; }
+    local parm="$1"
+    local val="$2"
+    run_remote_python "
+import hou
+nodes = hou.selectedNodes()
+if not nodes:
+    print('No nodes selected.')
+else:
+    p = nodes[0].parm('$parm')
+    if p is None:
+        print(f'Parameter \"$parm\" not found on {nodes[0].path()}')
+    else:
+        p.set('$val')
+        print(f'{nodes[0].path()}.{p.name()} = {p.eval()}  ✓')
+"
+}
+
+cmd_get_inputs() {
+    run_remote_python '
+import hou
+nodes = hou.selectedNodes()
+if not nodes:
+    print("No nodes selected.")
+else:
+    for n in nodes:
+        inputs = n.inputConnectors()
+        print(f"\n{n.path()} [{n.type().name()}]")
+        for i, conn in enumerate(inputs):
+            in_nodes = n.inputConnections(i) if hasattr(n, "inputConnections") else []
+            if in_nodes:
+                for c in in_nodes:
+                    print(f"  input {i} ← {c.inputNode().path()}  [{c.inputNode().type().name()}]")
+            else:
+                print(f"  input {i} ← (none)")
+'
+}
+
+# ── Main ─────────────────────────────────────────────────
+
+[[ $# -ge 1 ]] || usage
+
+CMD="$1"
+shift || true
+
+case "$CMD" in
+    eval)           cmd_eval "$@" ;;
+    script)         cmd_script "$@" ;;
+    get-selected)   cmd_get_selected ;;
+    get-param)      cmd_get_param "$@" ;;
+    set-param)      cmd_set_param "$@" ;;
+    get-inputs)     cmd_get_inputs ;;
+    status)         cmd_status ;;
+    help|--help|-h) usage ;;
+    *)
+        echo "Unknown command: $CMD"
+        usage
+        ;;
+esac
@@ -0,0 +1,113 @@
+# Hermes Skill: Houdini Bridge
+
+Standard workflows to control a running Houdini session via the hermes-houdini-bridge.
+
+## Trigger
+
+When the user asks to:
+- Modify node parameters in Houdini
+- Build node setups/networks in Houdini
+- Write VEX/Wrangle code in Houdini
+- Query selected nodes, connections, or scene state
+- Execute Python in a running Houdini session
+
+## Prerequisites
+
+1. User must have the Hermes Bridge shelf tool active in Houdini (port 12345 open)
+2. SSH access to the Houdini workstation (default: `niklas@192.168.178.39`)
+
+If the bridge is not open, tell the user: "Open the Hermes Bridge shelf tool in Houdini first."
+
+## Client Location
+
+`/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb`
+
+Always use this full path — the script handles SSH and hcommand internally.
+
+## Common Workflows
+
+### 1. Query Selected Nodes
+
+```bash
+/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb get-selected
+```
+
+### 2. Set a Parameter
+
+```bash
+/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb set-param <parm_name> <value>
+```
+Example: `hhb set-param file /path/to/texture.exr`
+
+### 3. Get a Parameter Value
+
+```bash
+/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb get-param <parm_name>
+```
+
+### 4. Execute Arbitrary Python
+
+```bash
+/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb eval "<python_code>"
+```
+
+The code runs in Houdini's Python environment with full `hou` module access.
+
+### 5. Check Connection
+
+```bash
+/opt/data/projects/hermes-houdini-bridge/hermes/bin/hhb status
+```
+
+## Useful hou Module Patterns
+
+### VEX in a Wrangler
+```python
+node = hou.selectedNodes()[0]
+node.parm('snippet').set('@P.y += sin(@Frame * 0.1);\n@Cd = rand(@ptnum);')
+```
+
+### Build a Node Chain
+```python
+obj = hou.node('/obj')
+geo = obj.createNode('geo', 'my_setup')
+null_in = geo.createNode('null', 'IN')
+wrangle = geo.createNode('attribwrangle', 'compute')
+null_out = geo.createNode('null', 'OUT')
+wrangle.setInput(0, null_in)
+null_out.setInput(0, wrangle)
+wrangle.parm('snippet').set('@Cd = rand(@ptnum);')
+wrangle.moveToGoodPosition()
+null_out.moveToGoodPosition()
+```
+
+### Read Node Info
+```python
+n = hou.selectedNodes()[0]
+info = {
+    'path': n.path(),
+    'type': n.type().name(),
+    'parms': {p.name(): p.eval() for p in n.parms() if not p.isAtDefault()},
+    'inputs': [c.inputNode().path() for c in n.inputConnections()],
+    'outputs': [c.outputNode().path() for c in n.outputConnections()],
+}
+print(info)
+```
+
+### Create a Material
+```python
+matnet = hou.node('/mat')
+principled = matnet.createNode('principledshader::2.0', 'my_material')
+principled.parm('basecolorr').set(1.0)
+principled.parm('basecolorg').set(0.2)
+principled.parm('basecolorb').set(0.1)
+principled.parm('rough').set(0.3)
+```
+
+## Pitfalls
+
+- Complex Python with quotes/backticks: Use `hhb script file.py` instead of `hhb eval "..."` 
+- Parameter names are internal (e.g., `file`, not `File`)
+- Node types: check with `node.type().name()` first
+- hcommand timeouts: complex scripts may take time, especially if triggering cooks
+- Selected node counts: always check `len(hou.selectedNodes())` before operating