Technical Abstract: User-friendly interfaces are prerequisite for acceptance of crop models. Currently, the outputs of most crop models are tables and 2-D graphs. However, users make tactical management decisions from visual observations of plants. A 3-D presentation of crop growth may provide users with a more useful model output. An open parametric Lindenmayer Systems (L-systems) model was developed using data and the L-Studio L-systems software. Two distinct soybean (Glycine max L.) cultivars, (traditional Essex and newly developed Moon Cake) were grown from emergence to seed filling in controlled climate chambers at two temperature regimes, 26/21oC and 32/27oC (day/night) from April 1 through June 9, 2003. Detailed morphological observations and photographs were made weekly. Analysis of data showed that although both cultivars for both temperatures demonstrated very similar qualitative morphological characteristics, the quantitative difference was significant for both cultivars and temperature regimes. Basic morphological variables, i.e. plant height, number of nodes, internode length, and total leaf surface area were described by three- or four-parametric sigmoidal functions of time, or stage of development, with different parameters for each temperature and genotype. The L-systems virtual plants accurately simulated growth and development of these two soybean cultivars. The same L-systems model was used for all treatments; the effects of temperature and genotype were accounted for by L-systems parameters. A visual L-systems model of soybean can be used (a) for validating crop simulation models and (b) as a part of user interface, and may further the acceptance of crop model technology by producers.