Problem: It's challenging to draw curves in-mid air. Solution: use objects as surfaces and points-of-reference for drawing-upon, or for transforming drawings, to make it easier to draw in 3D.
How it works: The user’s perspective determines the shape of line strokes he/she draws. Lines are projected onto the world as they are drawn or moved. The user can spawn objects to draw-on, and can transform (reposition, rotate) those objects to influence lines drawn on those objects.
User-drawn lines are projected onto geometry in the background. A drawing appears normal from an initial perspective, but when the user moves, it becomes clear that the drawing has been projected along—for example—a cave wall. A user may draw along irregular surfaces or create reference geometry (e.g. sphere, cube) onto which he/she can sketch lines. For example, one might create a sphere, point at its equator, hold the draw button in-place, and rotate the sphere on the y-axis to trace a circular path around the equator. Deleting the sphere would leave a circular path. Alternatively, one could point at the center of the sphere, hold draw, and walk around the sphere (comparable to a sculptor’s way of thinking). Implementation: Unity engine project using HTC Vive.