Glass box: views in first- and third-angle projection
About this app
A part in a glass box casts its six views onto the walls to ISO 5456-2: visible edges as thick continuous lines, hidden ones dashed, centre lines as chain lines, computed exactly from the geometry. The box unfolds into the standard arrangement (first or third angle, with projection symbol). Tap a face or edge and it lights up in every view; four machine parts, rotatable, with a quiz on views and their positions.
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
What it is about
Engineering drawings show a part in orthographic projection: parallel rays stand perpendicular to the drawing plane. The thinking model is the glass box. Each of its six walls receives one view, from the front view A to the view from the rear F. In first-angle projection (method 1, ISO 5456-2) the part lies between observer and plane. Unfolding the box puts the top view below the front view and the view from the left to its right. Third angle (method 3) is the other way round. The projection symbol in the title block tells which method applies.
What the app shows
Four machine parts are available: bearing block, slotted bracket, stepped flange with a pitch circle and guide block with slope and V-groove. The app computes every view from the geometry. Visible edges appear as wide continuous lines, hidden edges as narrow dashed lines, centre lines as long-dashed dotted lines to ISO 128. Projection rays show how each view arises. At the press of a button the walls fold into the drawing plane and the projection symbol appears.
Try it yourself
Tap a face or an edge: it lights up in all six views, and the panel tells you whether it is visible, hidden or seen only as a line. Turn the part in 90-degree steps inside the box and watch all views change. Switch between method 1 and method 3 and see the views travel through the part to the opposite wall. Practice mode asks: which view is this, and where does it go in method 1?
Frequently asked questions
- What is the difference between first-angle and third-angle projection?
- In first angle (method 1) the part lies between observer and projection plane, so the top view sits below the front view and the view from the left to its right. In third angle (method 3) the plane lies between observer and part, so the top view sits above the front view and the view from the left on the left.
- How do I read the projection symbol?
- The symbol to ISO 5456-2 shows a truncated cone as a trapezium and as two concentric circles. Circles to the right of the trapezium mean first angle, circles to the left mean third angle.
- How are hidden edges drawn?
- To ISO 128 as narrow dashed lines (line type 02.1). Visible edges are wide continuous lines, centre and symmetry lines narrow long-dashed dotted lines.
- What can I do in the Glass box app?
- Choose a part, turn it in the box, toggle projection rays, hidden edges and centre lines, unfold the box into the standard arrangement and practise recognising and placing views.
Subject: Technical drawing
More from Technical drawing
A VisuApp by heyprof: interactive, free in your browser, no sign-up. What is a VisuApp? · All apps