r/GeometryIsNeat

Image 1 — Sawtooth Polyhedral
Image 2 — Sawtooth Polyhedral

Sawtooth Polyhedral

My latest polyhedral build. 60 faces. 3D printed frame, laser cut clear acrylic faces with UV printed pattern.

u/pubultrastar — 14 hours ago

A hand-drafted Voronoi diagram

This is just the skeleton grid for an ink drawing. I'm still trying to decide how I'll ink it. But yeah, here's a hand-drafted Voronoi diagram of a 55:89 parastichy spiral phyllotaxis pattern using Vogel's formula. I've done this in a vector art program as well, and honestly I'm not sure which technique was faster: by computer, or by hand. By hand is messier but this will all get inked over. I used Euclid's ruler and compass method for finding a perpendicular midpoint line on each space between nodes.

u/a_smiling_friend — 8 days ago
▲ 11 r/GeometryIsNeat+3 crossposts

Orthographic to Isometric Drawing Made Easy – First Angle Projection

 Problem Statement:
Convert this Orthographic drawing (given in First Angle Projection with Front and Top Views) into an Isometric Drawing.

📚 What You'll Learn:
• Drawing the isometric box from given dimensions (70 × 50 × 50)
• Identifying and drawing through holes
• Drawing L-shaped features in isometric projection
• Drawing inclined planes
• Verifying accuracy against orthographic views

🎯 Perfect for:
• Engineering Drawing students
• SSC CGL, Karnataka CET, ITI, Diploma, and B.Tech students
• Anyone preparing for technical exams in India

🙏 Support the Channel:
If this video helped you, please LIKE, SHARE, and SUBSCRIBE to "Draft & Dialogue" with Ephrem for more engineering drawing tutorials. Click the bell icon to never miss an update!

💬 Have Doubts?
Drop your questions in the comments – I personally read and reply to every comment.

#IsometricDrawing #OrthographicToIsometric #FirstAngleProjection #EngineeringDrawing #TechnicalDrawing #SSCJE #KarnatakaCET #ITIDrawing #DraftAndDialogue

youtube.com
u/Proud_Read7281 — 6 days ago
▲ 48 r/GeometryIsNeat+1 crossposts

ZRVTO between Phobos and Deimos

An animation of the Phobos Deimos ZRVTO (Zero Relative Velocity Transfer Orbit) as described by Paul Penzo on page 45 of the Tethers In Space Handbook: Link

If a payload is released at the right time from the top of 940 tether ascending from Phobos it will arrive at the foot of a 2960 km tether descending from Deimos.

At apoapsis the payload matches the velocity of the Deimos tether foot.

Thus Phobos can send payloads to Deimos with nearly zero propellant. And vice versa.

Penzo notes both Deimos and Phobos are huge momentum banks. So Phobos and Deimos anchored tethers can catch and throw payloads till the cows come home with very little effect on their orbits.

There is a ZRVTO between any two Sarmont tethers in circular orbits of the same inclination.

I believe Penzo's insight can be extremely useful.

Required tether mass goes up exponentially with delta V. Somewhat like propellant in Tsiolkovsky's rocket equation.

With a chain of Sarmont tethers connected by ZRVTOs, the delta V budget is broken into chunks. Thus you can have tethers made from today's materials without ridiculous taper ratios.

u/HopDavid — 13 days ago