The importance of line weights cannot be underscored in architectural drawings. Whether they are executed through a cherished set of technical pens or pencils, or through a well-loved reference sheet of plot styles taped to one’s monitor, line weights can add a substantial amount of information—depth, hierarchy, space, cut locations, materiality, door swings, reference points—to a drawing without requiring the addition of more objects or text. As Life of an Architect blogger Bob Borson, AIA, puts it: “You can incorporate more information into a single drawing and still have the document be legible.”

Perhaps it was inevitable then that Morpholio Apps, the New York–based studio intent on encapsulating the entire design-ideation process in their mobile apps, today launched ScalePen, a patent-pending way to draw with different line weights, or stroke thicknesses, in its Trace app (free, iPad and iPad Pro). As a user draws in Trace, ScalePen checks the drawing scale and zoom level and then dynamically assigns a calibrated set of technical pens appropriate for use at that view. No more getting stuck with heavyset strokes at a close-up view, or scrawny lines when zoomed out.

For example, a user working on the site plan at 1/16-inch scale will get an assigned set of 10 pens. Zoom in to work on the floor plan at 1/4-inch scale and Trace will present another set of 10 pens with smaller absolute line weights, but with the same workability for drawing details at the new scale. Zoom back out to the site plan, and the original array of 10 pens will return.

“No matter what zoom level you are in, there is a thinnest line and a thickest line relative to that zoom level,” Morpholio co-creator Toru Hasegawa says. “The tricky part is having a system that can cover them at all.” The analog method of drawing with technical pens didn’t require the vast range of line weights “because it was bounded to a paper size,” he says. “We can’t zoom into a physical paper.”

As one moves in and out of a drawing in Trace, the ScalePen animation quickly scrolls through pens to indicate it is queuing up the appropriate set. “It’s our way of minimizing mental distractions or mental side steps,” Hasegawa says. “The main priority should be focused on ideation and not becoming a master of choosing a pen.”

ScalePen can be used on eight pen types, including pencil, charcoal, and brush. Users with a designated set of tools for sketching, red-lining, or simply their own line-drawing style can set five favorite pen types along with their stroke size, opacity, and color.

Javier Galindo