Geometry tree and hierarchy

A single model built from several primitives organised into nested GeometryGroups, each item with its own mesh density and explicit tmm node numbering. We print the scene hierarchy with print_tree() and render one interactive plot with a distinct color per item and the mesh edges hidden.

Build the scene

import numpy as np
import pycanha_core as pcc

import pycanha as pc
from pycanha import gmm

pcc.set_logger_level(pcc.LogLevel.WARN)

TAU = 2 * np.pi


def simple_mesh(a=3, b=3):
    """A ThermalMesh with a small a-by-b UV subdivision."""
    return gmm.ThermalMesh(list(np.linspace(0, 1, a)), list(np.linspace(0, 1, b)))


def item(name, primitive, mesh, node_start):
    mesh.node1_start = node_start
    mesh.node2_start = node_start
    mesh.node1_step = 1  # number each face sequentially
    mesh.node2_step = 1
    return gmm.GeometryItem(name, primitive, mesh)


# Simple model: a body box (two panels), two solar panels, a dish.
body = gmm.GeometryGroup(
    "body",
    [
        item("top", gmm.Rectangle((0, 0, 1), (1, 0, 1), (0, 1, 1)), simple_mesh(3, 3), 100),
        item("bottom", gmm.Rectangle((0, 0, 0), (1, 0, 0), (0, 1, 0)), simple_mesh(2, 2), 200),
    ],
)
panels = gmm.GeometryGroup(
    "panels",
    [
        item(
            "panel_a", gmm.Rectangle((1.2, 0, 0), (2.2, 0, 0), (1.2, 1, 0)), simple_mesh(4, 2), 300
        ),
        item(
            "panel_b",
            gmm.Rectangle((-2.2, 0, 0), (-1.2, 0, 0), (-2.2, 1, 0)),
            simple_mesh(4, 2),
            400,
        ),
    ],
)
dish = item(
    "dish",
    gmm.Paraboloid((0, 0, 1.5), (0, 0, 1), (0.5, 0, 1.5), 0.5, 0.0, TAU),
    simple_mesh(3, 3),
    500,
)

tm = pc.ThermalModel("satellite")
tm.gmm.add(gmm.GeometryGroup("spacecraft", [body, panels, dish]))

The hierarchy

print_tree shows every group / item, its primitive, mesh size and node range.

tm.gmm.print_tree()

GeometryModel 'satellite'
`-- Group 'spacecraft'
    |-- Group 'body'
    |   |-- Item 'top'  Rectangle  mesh 2x2 (4 faces/side)  nodes 100..103
    |   `-- Item 'bottom'  Rectangle  mesh 1x1 (1 faces/side)  nodes 200..200
    |-- Group 'panels'
    |   |-- Item 'panel_a'  Rectangle  mesh 3x1 (3 faces/side)  nodes 300..302
    |   `-- Item 'panel_b'  Rectangle  mesh 3x1 (3 faces/side)  nodes 400..402
    `-- Item 'dish'  Paraboloid  mesh 2x2 (4 faces/side)  nodes 500..503

The model, one color per item, edges hidden

scalars="item" gives each geometry item a distinct color (no numeric scale). show_edges=False hides the triangular mesh.

print(f"world mesh: {tm.gmm.mesh.nt()} triangles")
tm.gmm.plot(scalars="item", show_edges=False, off_screen=True)

Static Scene

Interactive Scene

world mesh: 1172 triangles

<pyvista.plotting.plotter.Plotter object at 0x7604d4732e90>