This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project aims to facilitate the combined use of the IMOD and Chimera software packages in analysis of electron tomography (ET) data of cells and viruses. IMOD is the main program used for hand-segmentation of ET maps and is based largely on visualization of 2-dimensional data slices, while Chimera is primarily used for 3-dimensional visualization. IMOD also computes tomographic reconstructions from the 2-dimensional tilt series obtained in experiments. Complementary capabilities of IMOD and Chimera are frequently used by researchers analyzing ET data. IMOD is developed by David Mastronarde at the Boulder Laboratory for 3-D Electron Microscopy of Cells which is an NCRR Biomedical Technology Research Resource directed by Andreas Hoenger. This collaborative project undertakes improvements in IMOD and Chimera software to simplify the exchange of segmentation and map data between the programs.