Houdini has plugins that allow you to import an OSM file. For example an area of a city, bound by a rectangle of northeast and southwest latitudes and longitudes.
When you input the OSM data into Houdini it runs it through a small python script that calculates the area height in meters along the latitude (taking into consideration the curvature of the earth). Same for width in meters along longitude.
It then converts all the lat,lon points in the area and makes them relative to the southwest (min) corner, in the range of 0.0 to 1.0.
Finally it multiplies each point by the width and height values. This gives you points in a 2D plane, in meters that are scaled very closely to the source area.
What is this type of isolated projection called?