Engineering views

Engineering views

extensions/visual/ draws engineering results. MeshBuilder builds walls, pipes and ground as one geometry. Overlay draws text, labels, leader lines, arrows and color bars on a rendered frame. The textures give formed concrete, soil and riprap. Retaining walls gives the analysis that these views show.

Modules

Module	What it gives
mesh	MeshBuilder: triangle, smooth_triangle, quad, oriented, prism, loft, plate, tube, heightfield and geometry
overlay	Overlay with text, text_width and label, and fill_polygons, fill_rect, stroke_line, fill_disc and arrow
textures	formed_concrete_maps, soil_maps and riprap_maps

Build a mesh

MeshBuilder takes points in a z-up frame in meters: x east, y north, z up. It turns them into the y-up frame that three.js draws in. Texture coordinates are world meters, projected along the axis that the face is most nearly normal to. A texture that repeats every n meters has the same scale on every face.

• prism extrudes a section polygon along a straight run.
• loft sweeps a section between two placements. Use it for a mitered corner or a sloping top.
• plate makes a flat slab with holes through it, for example a headwall with pipe openings.
• tube makes a round pipe barrel, solid or hollow.
• heightfield makes a smooth surface over a grid of heights.

var mb = MeshBuilder()
mb.prism([(0.0, 0.0), (3.0, 0.0), (3.0, 0.5), (0.0, 0.5)], Vec3d(0, 0, 0), Vec3d(0, 5, 0), Vec3d(1, 0, 0), Vec3d(1, 1, 1))
var geometry = mb.geometry()

Annotate a frame

Overlay.from_ttf loads a TrueType font. text draws one line at a baseline, anchored LEFT, CENTER or RIGHT. label draws lines of text on a box, with an optional colored bar. Every shape is filled by the even-odd rule with 4 by 4 samples per pixel, then blended over the frame.

Use the camera's project to put a world point on the frame. Then draw a leader line from the label to the point.

Glyph contours

The overlay fills every contour of a glyph by the even-odd rule. It does not sort the contours into shapes with holes. A font can list a hole before its outline, as DejaVu Sans does for "8". The to_shapes method of ShapePath keeps the three.js behavior and drops such a hole. The overlay draws it correctly.

Limits

• The overlay draws in sRGB bytes. It does not tone map.
• Text is one line per call. label stacks lines.