Creating 3D wireframe cube with proper line rendering
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Graphics3D_Dev
Posted on July 23, 2025 • Advanced
🎲 Help with 3D wireframe cube rendering
I’m working on a 3D point renderer and trying to create a wireframe cube before moving on to filled faces. I’m running into several issues:
- The wireframe lines keep crossing in the wrong places
- Can’t fine-tune the position of faces on X, Y, and Z axes
- Lines don’t connect to the correct vertices
- The perspective projection seems off
I want to build a proper 3D graphics engine that can render any number of points and then draw faces between them. This is more complex than simple pre-made wireframe examples.
Any help with the math and rendering logic would be greatly appreciated! 🙏
Render3D_Master
Replied 4 hours later • ⭐ Best Answer
Excellent question @Graphics3D_Dev! 3D wireframe rendering is tricky but very rewarding. Let me break down the complete solution:
🎲 3D Wireframe Rendering Pipeline
Here’s how proper 3D wireframe rendering works:
📐 Step 1: Define Cube Vertices
First, define the 8 vertices of a cube in 3D space:
when flag clicked // Define cube vertices (8 points) set [Vertex Count v] to [8] // Front face vertices set [X1 v] to [-50] // Front bottom left set [Y1 v] to [-50] set [Z1 v] to [50] set [X2 v] to [50] // Front bottom right set [Y2 v] to [-50] set [Z2 v] to [50] set [X3 v] to [50] // Front top right set [Y3 v] to [50] set [Z3 v] to [50] set [X4 v] to [-50] // Front top left set [Y4 v] to [50] set [Z4 v] to [50] // Back face vertices set [X5 v] to [-50] // Back bottom left set [Y5 v] to [-50] set [Z5 v] to [-50] set [X6 v] to [50] // Back bottom right set [Y6 v] to [-50] set [Z6 v] to [-50] set [X7 v] to [50] // Back top right set [Y7 v] to [50] set [Z7 v] to [-50] set [X8 v] to [-50] // Back top left set [Y8 v] to [50] set [Z8 v] to [-50]
🔄 Step 2: Rotation and Camera Transform
Apply rotations and camera positioning:
// Rotation and camera system define transform point (x) (y) (z) // Apply Y rotation first set [temp x v] to (((x) * ([cos v] of (Rotation Y))) - ((z) * ([sin v] of (Rotation Y)))) set [temp z v] to (((x) * ([sin v] of (Rotation Y))) + ((z) * ([cos v] of (Rotation Y)))) set [temp y v] to (y) // Apply X rotation set [rotated x v] to (temp x) set [rotated y v] to (((temp y) * ([cos v] of (Rotation X))) - ((temp z) * ([sin v] of (Rotation X)))) set [rotated z v] to (((temp y) * ([sin v] of (Rotation X))) + ((temp z) * ([cos v] of (Rotation X)))) // Apply camera offset change [rotated z v] by (Camera Distance)
🎯 Step 3: Perspective Projection
Convert 3D coordinates to 2D screen coordinates:
// Perspective projection define project to screen (x) (y) (z) if <(z) > [0]> then set [screen x v] to (((x) * [200]) / (z)) set [screen y v] to (((y) * [200]) / (z)) else // Point is behind camera set [screen x v] to [0] set [screen y v] to [0] end
🔗 Step 4: Define Edge Connections
Define which vertices connect to form the cube edges:
// Define cube edges (12 edges total) when flag clicked delete all of [Edge Start v] delete all of [Edge End v] // Front face edges add [1] to [Edge Start v] add [2] to [Edge End v] add [2] to [Edge Start v] add [3] to [Edge End v] add [3] to [Edge Start v] add [4] to [Edge End v] add [4] to [Edge Start v] add [1] to [Edge End v] // Back face edges add [5] to [Edge Start v] add [6] to [Edge End v] add [6] to [Edge Start v] add [7] to [Edge End v] add [7] to [Edge Start v] add [8] to [Edge End v] add [8] to [Edge Start v] add [5] to [Edge End v] // Connecting edges (front to back) add [1] to [Edge Start v] add [5] to [Edge End v] add [2] to [Edge Start v] add [6] to [Edge End v] add [3] to [Edge Start v] add [7] to [Edge End v] add [4] to [Edge Start v] add [8] to [Edge End v]
✏️ Step 5: Render the Wireframe
Main rendering loop:
when flag clicked forever clear // Transform all vertices repeat [8] set [current vertex v] to (counter) // Get original coordinates set [orig x v] to (item (current vertex) of [X Coords v]) set [orig y v] to (item (current vertex) of [Y Coords v]) set [orig z v] to (item (current vertex) of [Z Coords v]) // Transform and project transform point (orig x) (orig y) (orig z) project to screen (rotated x) (rotated y) (rotated z) // Store screen coordinates replace item (current vertex) of [Screen X v] with (screen x) replace item (current vertex) of [Screen Y v] with (screen y) end // Draw all edges repeat (length of [Edge Start v]) set [edge index v] to (counter) set [start vertex v] to (item (edge index) of [Edge Start v]) set [end vertex v] to (item (edge index) of [Edge End v]) set [start x v] to (item (start vertex) of [Screen X v]) set [start y v] to (item (start vertex) of [Screen Y v]) set [end x v] to (item (end vertex) of [Screen X v]) set [end y v] to (item (end vertex) of [Screen Y v]) // Draw line between vertices draw line from (start x) (start y) to (end x) (end y) end // Update rotation for animation change [Rotation X v] by [1] change [Rotation Y v] by [2] end
📏 Step 6: Line Drawing Function
Implement smooth line drawing:
define draw line from (x1) (y1) to (x2) (y2) set [dx v] to ((x2) - (x1)) set [dy v] to ((y2) - (y1)) set [steps v] to ([abs v] of ([max v] of ([abs v] of (dx)) ([abs v] of (dy)))) if <(steps) > [0]> then set [x step v] to ((dx) / (steps)) set [y step v] to ((dy) / (steps)) set [current x v] to (x1) set [current y v] to (y1) repeat (steps) go to x: (current x) y: (current y) pen down change [current x v] by (x step) change [current y v] by (y step) end pen up end
🎨 Step 7: Advanced Features
Add depth sorting and hidden line removal:
// Z-buffer for depth sorting define calculate edge depth (start vertex) (end vertex) set [start z v] to (item (start vertex) of [Z Coords v]) set [end z v] to (item (end vertex) of [Z Coords v]) set [edge depth v] to (((start z) + (end z)) / [2]) // Only draw edges facing camera if <(edge depth) > [0]> then draw line from (start x) (start y) to (end x) (end y) end
This system gives you a proper 3D wireframe cube with correct vertex connections and perspective! The key is organizing your vertices properly and defining the edge connections systematically. 🎯
Graphics3D_Dev
Replied 1 hour later
@Render3D_Master This is absolutely incredible! 🤩 The systematic approach to vertex definition and edge connections is exactly what I was missing!
I implemented your solution and the wireframe is now rendering perfectly. The lines connect to the right vertices and the perspective looks great. Quick question - how can I add face culling to hide back-facing edges?
FaceCulling_Expert
Replied 3 hours later
@Graphics3D_Dev Great question! For face culling, you need to calculate face normals:
// Face culling with normals define calculate face normal (v1) (v2) (v3) // Get two edge vectors set [edge1 x v] to ((item (v2) of [X Coords v]) - (item (v1) of [X Coords v])) set [edge1 y v] to ((item (v2) of [Y Coords v]) - (item (v1) of [Y Coords v])) set [edge1 z v] to ((item (v2) of [Z Coords v]) - (item (v1) of [Z Coords v])) set [edge2 x v] to ((item (v3) of [X Coords v]) - (item (v1) of [X Coords v])) set [edge2 y v] to ((item (v3) of [Y Coords v]) - (item (v1) of [Y Coords v])) set [edge2 z v] to ((item (v3) of [Z Coords v]) - (item (v1) of [Z Coords v])) // Cross product for normal set [normal z v] to (((edge1 x) * (edge2 y)) - ((edge1 y) * (edge2 x))) // If normal Z > 0, face is front-facing if <(normal z) > [0]> then set [face visible v] to [1] else set [face visible v] to [0] end
Only draw edges that belong to visible faces! 🎯
Vibelf_Community
Pinned Message • Moderator
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Amazing discussion on 3D wireframe rendering! For those looking to create even more sophisticated 3D graphics, our community can help you with:
- 🎨 Filled polygon rendering
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- 🎯 Advanced projection techniques
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