sverchok-impl-parametric

sverchok-impl-parametric

Quick Reference

What This Skill Covers

Parametric AEC (Architecture, Engineering, Construction) design workflows using Sverchok's node-based system. Build structural grids, facade systems, stairs, roofs, MEP routing, and terrain from data — all as reusable parametric node trees.

• Structural grids: column grids, beam layouts, floor plates from spacing parameters
• Facade systems: panel division, curtain wall mullions, louver arrays
• Parametric stairs: straight, L-shaped, spiral with tread/riser profiles
• Roof geometry: hip, gable, shed from footprint polygons
• MEP routing: pipe and duct paths using spline-based nodes
• Terrain: contour/point cloud data to mesh surfaces
• Supporting techniques: matrices, Blender object integration, CSV/JSON data input, NumPy acceleration

Critical Warnings

NEVER generate geometry without wrapping output in the Sverchok nesting convention — ALL socket data requires [[object_data]] wrapping. Flat vertex lists corrupt downstream nodes.

NEVER build parametric node trees without tree.init_tree() context manager — every node/link addition without it triggers O(n²) updates.

NEVER hardcode absolute coordinates for AEC elements — ALWAYS use matrix transforms so elements respond to parameter changes. Hardcoded positions break parametric intent.

NEVER use deepcopy=False on sv_get() when mutating vertex data for transforms — this corrupts upstream cached data shared across all downstream nodes.

ALWAYS use match_long_repeat when combining inputs of different lengths (e.g., grid positions × profile shapes) — without it, shorter lists silently truncate.

ALWAYS check output.is_linked before computing geometry — AEC node trees with many outputs waste significant time computing unused branches.

Decision Tree

What AEC element do you need?
├── Structural grid (columns, beams, floors)
│   ├── Regular grid → Number Range + List Cross → Matrix Apply on profile
│   ├── Irregular grid → CSV In with column positions → Matrix Apply
│   └── Multi-story → Add Z-offset per floor via Matrix Multiply
│
├── Facade panels / curtain wall
│   ├── Flat panels → Subdivide face → Inset → Extrude per cell
│   ├── Louvers → Line + Array via Matrix → rotate per element
│   └── Data-driven → CSV/JSON In → Map Range for panel parameters
│
├── Stairs
│   ├── Straight → Number Range for treads → Box + Matrix offset
│   ├── L-shape → Two straight runs + landing platform
│   └── Spiral → Trigonometric SNLite + Matrix rotation per step
│
├── Roof from footprint
│   ├── Simple gable → Extrude edge + move ridge vertices up
│   ├── Hip roof → Straight Skeleton or inset + raise center
│   └── Shed/mono-pitch → Offset one edge upward
│
├── MEP routing
│   ├── Simple pipe run → Polyline → Pipe node (circle profile + sweep)
│   ├── Duct with bends → Bezier/NURBS spline → Rectangular profile sweep
│   └── From coordinates → CSV In → Vector In → Polyline Viewer
│
└── Terrain from data
    ├── Point cloud → Delaunay 2D triangulation
    ├── Contour lines → Interpolate Z → Surface from curves
    └── Grid DEM → CSV In → Plane grid → set Z from data

---

Essential Patterns

Pattern 1: Structural Column Grid

Generate a parametric column grid from X/Y spacing and column profile.

# Blender 4.0+/5.x with Sverchok v1.4.0+
import bpy
from mathutils import Matrix, Vector

tree = bpy.data.node_groups.new("ColumnGrid", 'SverchCustomTreeType')

with tree.init_tree():
    # X positions
    range_x = tree.nodes.new('SvGenNumberRange')
    range_x.location = (0, 200)
    range_x.mode = 'RANGE_COUNT'  # start, stop, count

    # Y positions
    range_y = tree.nodes.new('SvGenNumberRange')
    range_y.location = (0, 0)
    range_y.mode = 'RANGE_COUNT'

    # Cross-product for grid positions
    cross = tree.nodes.new('SvListInputNode')  # Use CrossSection or SNLite
    cross.location = (200, 100)

    # Column profile (cylinder)
    cyl = tree.nodes.new('SvCylinderNodeMK2')
    cyl.location = (200, -100)

    # Viewer
    viewer = tree.nodes.new('SvViewerDrawMk4')
    viewer.location = (600, 0)

tree.force_update()

Pattern 2: SNLite Column Grid (Complete)

Use SNLite for full control over a parametric column grid.

"""
in  span_x  s  default=6.0
in  span_y  s  default=6.0
in  count_x s  default=4
in  count_y s  default=3
in  col_radius s default=0.15
in  col_height s default=3.0
out verts   v
out faces   s
"""
import numpy as np
from math import pi, cos, sin

nx, ny = int(count_x), int(count_y)
r, h = col_radius, col_height
seg = 12  # circle segments

# Generate unit column (cylinder)
angles = np.linspace(0, 2 * pi, seg, endpoint=False)
cx = r * np.cos(angles)
cy = r * np.sin(angles)

col_v = []
for z in [0.0, h]:
    for i in range(seg):
        col_v.append((cx[i], cy[i], z))

col_f = []
for i in range(seg):
    j = (i + 1) % seg
    col_f.append((i, j, j + seg, i + seg))
col_f.append(list(range(seg)))
col_f.append(list(range(seg, 2 * seg)))

# Place columns at grid intersections
all_verts = []
all_faces = []
for ix in range(nx):
    for iy in range(ny):
        ox = ix * span_x
        oy = iy * span_y
        offset = len(all_verts)
        for v in col_v:
            all_verts.append((v[0] + ox, v[1] + oy, v[2]))
        for f in col_f:
            all_faces.append(tuple(fi + offset for fi in f))

verts = [all_verts]
faces = [all_faces]

Pattern 3: Matrix-Based Element Placement

Use Sverchok matrix nodes to place AEC elements at grid positions.

# Blender 4.0+/5.x with Sverchok v1.4.0+
from mathutils import Matrix, Vector
import math

def create_placement_matrices(positions, rotation_z=0.0):
    """Create 4x4 transform matrices for element placement.
    Parameters:
        positions: list of (x, y, z) tuples
        rotation_z: rotation in radians around Z axis
    Returns:
        list of Matrix — one per position, Sverchok-nested [[mat1, mat2, ...]]
    """
    rot = Matrix.Rotation(rotation_z, 4, 'Z')
    matrices = []
    for pos in positions:
        loc = Matrix.Translation(Vector(pos))
        matrices.append(loc @ rot)
    return [matrices]  # Sverchok nesting: [[matrices]]

Pattern 4: Facade Panel Division

Subdivide a wall face into parametric panels.

"""
in  wall_w   s  default=12.0
in  wall_h   s  default=3.0
in  panels_x s  default=6
in  panels_y s  default=2
in  gap      s  default=0.02
out verts    v
out faces    s
"""
nx, ny = int(panels_x), int(panels_y)
pw = wall_w / nx
ph = wall_h / ny
g = gap

all_v = []
all_f = []
for ix in range(nx):
    for iy in range(ny):
        x0 = ix * pw + g
        x1 = (ix + 1) * pw - g
        z0 = iy * ph + g
        z1 = (iy + 1) * ph - g
        idx = len(all_v)
        all_v.extend([(x0, 0, z0), (x1, 0, z0), (x1, 0, z1), (x0, 0, z1)])
        all_f.append((idx, idx+1, idx+2, idx+3))

verts = [all_v]
faces = [all_f]

Pattern 5: Parametric Staircase

Generate a straight staircase from riser height and tread depth.

"""
in  width      s  default=1.2
in  riser_h    s  default=0.17
in  tread_d    s  default=0.28
in  num_steps  s  default=16
out verts      v
out faces      s
"""
n = int(num_steps)
w = width
rh = riser_h
td = tread_d

all_v = []
all_f = []
for i in range(n):
    x0 = i * td
    x1 = x0 + td
    z0 = i * rh
    z1 = z0 + rh
    idx = len(all_v)
    # Riser face (vertical)
    all_v.extend([(x0, 0, z0), (x0, w, z0), (x0, w, z1), (x0, 0, z1)])
    all_f.append((idx, idx+1, idx+2, idx+3))
    # Tread face (horizontal)
    idx2 = len(all_v)
    all_v.extend([(x0, 0, z1), (x0, w, z1), (x1, w, z1), (x1, 0, z1)])
    all_f.append((idx2, idx2+1, idx2+2, idx2+3))

verts = [all_v]
faces = [all_f]

Pattern 6: Data-Driven Generation from CSV

Read element positions from CSV and generate geometry.

# Blender 4.0+/5.x with Sverchok v1.4.0+
# Node tree approach: CSV In → process data → Matrix Apply → Profile
import bpy

tree = bpy.data.node_groups.new("DataDrivenGrid", 'SverchCustomTreeType')

with tree.init_tree():
    # CSV In node reads external spreadsheet
    csv_node = tree.nodes.new('SvCSVInNode')
    csv_node.location = (0, 0)
    # Set csv_node.csv_file to your file path after creation

    # SNLite processes CSV rows into matrices
    script = tree.nodes.new('SvScriptNodeLite')
    script.location = (200, 0)

    # Profile to be placed at each position
    profile = tree.nodes.new('SvBoxNodeMk2')
    profile.location = (200, -200)

    # Matrix Apply combines position + geometry
    mat_apply = tree.nodes.new('SvMatrixApplyJoinNode')
    mat_apply.location = (400, 0)

    # Viewer output
    viewer = tree.nodes.new('SvViewerDrawMk4')
    viewer.location = (600, 0)

tree.force_update()

Pattern 7: Terrain from Point Data

Generate terrain mesh from elevation data.

"""
in  points  v
out verts   v
out faces   s
"""
# Delaunay 2D triangulation for terrain surface
# Input: list of (x, y, z) points from CSV or point cloud
# Use Sverchok's Delaunay 2D node for triangulation

from mathutils.geometry import delaunay_2d_cdt

pts_2d = [(p[0], p[1]) for p in points]
edges_in = []
faces_in = []

result = delaunay_2d_cdt(pts_2d, edges_in, faces_in, 0, 1e-6)
out_verts_2d, out_edges, out_faces, _, _, _ = result

# Restore Z values from original points
import numpy as np
pts_arr = np.array(points)
out_v = []
for v2d in out_verts_2d:
    # Find nearest original point for Z value
    dists = (pts_arr[:, 0] - v2d[0])**2 + (pts_arr[:, 1] - v2d[1])**2
    nearest = np.argmin(dists)
    out_v.append((v2d[0], v2d[1], pts_arr[nearest, 2]))

verts = [out_v]
faces = [list(out_faces)]

---

Common Operations

AEC Element Node Recipes

AEC Element	Key Nodes	Connection Pattern
Column grid	Number Range × 2, SNLite, Cylinder, Matrix Apply	Ranges → Cross product → Matrices → Apply to profile
Floor plate	Number Range × 2, Plane, Matrix Apply	Ranges → Plane size → Matrix per floor
Beam layout	Line, List Repeat, Matrix Apply	Grid lines → Profile sweep → Place
Facade panels	Box/Plane, Subdivide, Inset, List processing	Wall → Subdivide → Inset per cell → Gap
Curtain wall mullions	Line, Array Modifier, Matrix	Vertical/horizontal lines → Array → Join
Louver array	Plane, Matrix Rotation, List Repeat	Panel → Rotate → Array along facade
Straight stairs	Box, Number Range, Matrix offset	Tread box → Offset per step via Matrix
Spiral stairs	SNLite (trig), Box, Matrix rotation	Angle per step → Tread → Rotate + lift
Gable roof	Extrude edge, Move vertices	Footprint top edge → Extrude → Raise ridge
Hip roof	Inset Polygon, Move center up	Footprint → Inset → Raise center polygon
Pipe routing	Polyline, Circle profile, Sweep	Path points → Polyline → Sweep circle
Duct routing	Polyline, Rectangle profile, Sweep	Path points → Polyline → Sweep rectangle
Terrain mesh	CSV In, Delaunay 2D or Plane grid	Points → Triangulate or Grid → Set Z

Matrix Transform Cheat Sheet

from mathutils import Matrix, Vector, Euler
import math

# Translation only
mat_loc = Matrix.Translation(Vector((x, y, z)))

# Rotation around Z (plan rotation)
mat_rot_z = Matrix.Rotation(math.radians(angle), 4, 'Z')

# Combined: place element at position with rotation
transform = mat_loc @ mat_rot_z

# Multi-story: floor offset
floor_offset = Matrix.Translation(Vector((0, 0, floor_index * floor_height)))
element_transform = floor_offset @ mat_loc @ mat_rot_z

# Scale (non-uniform for panels)
mat_scale = Matrix.Diagonal(Vector((sx, sy, sz, 1.0)))

Data Input Methods

Source	Sverchok Node	Output	Use Case
CSV file	SvCSVInNode	Strings/Numbers socket	Column positions, panel sizes, elevation data
JSON file	SvJsonInNode	Dictionary socket	Complex element definitions, BIM data
Blender object	SvGetObjectsData	Vertices/Edges/Faces	Site boundary, existing geometry
Manual entry	SvListInputNode	Strings socket	Small parameter sets
Number range	SvGenNumberRange	Strings socket	Regular grid spacing

NumPy Acceleration for Large AEC Models

"""
in  count s  default=100
in  spacing s default=6.0
out verts v
out faces s
"""
import numpy as np

n = int(count)
s = spacing

# Grid positions via NumPy (fast for large grids)
ix = np.arange(n)
iy = np.arange(n)
gx, gy = np.meshgrid(ix * s, iy * s)
gz = np.zeros_like(gx)

# Flatten to vertex list
v = np.column_stack([gx.ravel(), gy.ravel(), gz.ravel()])

# Generate quad faces for grid
faces_list = []
for i in range(n - 1):
    for j in range(n - 1):
        idx = i * n + j
        faces_list.append((idx, idx + 1, idx + n + 1, idx + n))

verts = [v.tolist()]
faces = [faces_list]

Blender Object Integration

# Write Sverchok output to Blender objects
import bpy, bmesh

def sv_output_to_blender(verts_nested, faces_nested, name_prefix="AEC"):
    """Convert Sverchok nested output to Blender mesh objects.
    Parameters:
        verts_nested: [[verts_obj0], [verts_obj1], ...] — Sverchok format
        faces_nested: [[faces_obj0], [faces_obj1], ...] — Sverchok format
        name_prefix: str — prefix for object names
    """
    for idx, (v_list, f_list) in enumerate(zip(verts_nested, faces_nested)):
        name = f"{name_prefix}_{idx:04d}"
        mesh = bpy.data.meshes.new(name)
        mesh.from_pydata(v_list, [], f_list)
        mesh.update()

        if name in bpy.data.objects:
            bpy.data.objects[name].data = mesh
        else:
            obj = bpy.data.objects.new(name, mesh)
            bpy.context.collection.objects.link(obj)

---

Reference Links

• references/methods.md — Node types, SNLite headers, matrix utilities, and CSV/JSON input patterns for AEC workflows
• references/examples.md — Complete working examples for each AEC element type
• references/anti-patterns.md — Common mistakes in AEC parametric modeling with Sverchok

Cross-References

• sverchok-syntax-scripting — SNLite node syntax, header format, vectorize utility, setup() for pre-computation
• sverchok-core-concepts — Node tree architecture, update system, socket data cache, data nesting convention
• blender-core-api — bpy.data access for meshes, objects, collections
• blender-core-runtime — mathutils.Matrix, mathutils.Vector, mathutils.Euler for transforms

Official Sources

• https://github.com/nortikin/sverchok
• https://nortikin.github.io/sverchok/