Elements -Descriptive Geometry

Android project in Java, without external dependencies (Android SDK only).

Languages

English (default), Bulgarian, French, German, Spanish. "Language" button on the main screen; the selection is saved and is independent of the device language.

Modes

Point A – projections A′ and A″

Segment AB – horizontal and frontal spread, true size by rotation

Plane ABC – spreads on the plane

Line DE ∩ plane ABC – intersection point I, check if it is in the triangle, visibility

Plane ABC ∩ plane DEF – intersection, common segment of triangles, visibility

Bodies (the "Bodies" button)

Sphere, right cone and right regular prism (vertical axis), up to two bodies

Contours in both projections, intersection line of both bodies, section with plane ABC (with spreads)

The curves are found numerically on a triangular mesh of the surface (accuracy – linear approximation)

Visibility: ray from point to observer (V: +y, H: +z); invisible is dashed line

Visibility

The observer at V looks from the front (larger y = closer), at H – from above (larger z = closer).