The U.S. Army universal camouflage trials took place from 2002 to 2004 with the goal of creating a single pattern that would provide adequate concealment in all environments. Four different patterns in a total of 13 variations were tested during the evaluation: three woodland patterns, three desert, three urban, three desert/urban, and one multi-environment pattern. The Universal Camouflage Pattern (UCP) found on the Army Combat Uniform was eventually adopted despite not having been part of the test.
Six patterns were originally developed in early 2002 and reviewed for effectiveness, with three of the six designs being rejected due to limited effectiveness. The final three patterns were evaluated at the U.S. Army Natick Soldier Center, and four color schemes were created for each pattern. The woodland patterns consisted of tan, green, brown and black; the desert patterns tan, dark tan, khaki and brown; the urban patterns tan, light gray, medium gray and black, and the desert/urban patterns contained tan, dark tan, light gray and brown. A common ground shade, tan, was selected for all patterns to allow individual equipment to be interchangeable if more than one color scheme were adopted. The patterns were All Over Brush, Shadow Line, Track, and Scorpion, co-developed with contractor Crye Precision. The goal was to develop a single pattern that would perform well in all terrains.
All Over Brush consisted of swirls of colors similar to patches of grass and brush. In a poll from the Army Times in 2002, All Over Brush was voted the most popular pattern in the woodland, desert, and urban schemes. The urban and desert/urban schemes were eliminated in the first phase of testing, with woodland being eliminated during the second phase of testing. Desert All Over Brush made it through phase three and four in a modified, more all-environment friendly form.
The Shadow Line pattern sported horizontal lines with slashes. All four color combinations were eliminated during the first phase of testing.
The Track pattern featured vertical lines with small, irregular marks present throughout. All four color combinations made it to phase two of testing, with a modified woodland pattern and modified urban pattern making it through phases three and four.
Scorpion was developed in conjunction with defense contractor Crye Precision. The pattern consists of six colors with an irregular spread throughout, and was designed to be effective in multiple environments. Following the trials, Crye began producing a slightly altered version for the commercial market as MultiCam.