
| <input file> | 3D model to be projected |
| [out=<file>] | Output file. Default is 'proj.img' |
| [prop=<dtheta>] | Most common option. Generates projections with a relatively uniform projection density in the unit triangle. |
| [perturb] | Used with prop to generate variations within the Euler angle distribution to reduce deterministic artifacts in Fourier space |
| [4point[=<az>]] | Generates 4 projections. 1 polar and 3 equatorial. Optional Az will rotate the top view. |
| [euler=<alt>,<az>,<phi>] | Generate a single projection with the given orientation |
| [list=<euler file>] | Generate projections from a list of orientations |
| [spiral=<angles>] | Generate projections along a spiral from axis to equator |
| [grid=<steps>] | Generate projections on an rectangular alt/az mesh, nonuniform projection density |
| [reproj=<class file>] | Give the name of a file with class-averages, and the model will be reprojected at corresponding angles. |
| [mask=<radius>] | Specify a circular mask radius for the projections |
| [text] | Dumps Euler angles to a text file |
| [sym=<c4,icos,etc>] | Specify symmetry of model to prevent redundant projections |
| [icos5fhalfmap] | Specify that the input map is an icos 5f map |
| [pad=<newsize>] | Used in Fourier mode |
| [mode=<1-6>] | Default is real-space projection, this specifies various Fourier modes |
| [phitoo[=<ang>]] | This will also vary phi in the final file. Warning: This works only with prop= and generates a LOT of projections. |
| [smear] | Used in conjunction with 'phitoo', this will rotationally smear between phi steps. |
| [phicomp] | This will roughly compensate for in-plane rotation from az with phi |
| [randomphi] | Randmomize phi (usually zero in most modes) |
| [randomall[=<altmin>,<altmax>,<azmin>,<azmax>,<phimin>,<phimax>]] | Randomize all 3 Eulers. |
| [frac=<0 to d-1>/<d>] | Generate a subset of the projections, used for parallel processing |
| [minalt=<ang>] | Minimum projection altitude |
| [makemask] | This will generate a output mask rather than a projection |
| [mrc2voltable] | For large maps, this option can save memory by reading directly into a masked memory structure |
project3d threeed.4a.mrc prop=5 sym=c4
This program generates a set of projections from a 3D model. Fourier space projection is much faster than real-space projection, but also produces fairly severe artifacts (much more severe than Fourier space reconstruction). This effect can be viewed with v4 The default 'mode' is -1, which is real-space projection with trilinear interpolation. This produces artifacts in Fourier space, but is quite good in real space. If mode > 0, the mode specifies the interpolation size in voxels. That is, mode=3 denotes 3x3x3 Gaussian interpolation in Fourier space. For most purposes, the default mode of -1 should be used.
The orientations to use for projections can be specified many different ways. The spiral option produces the most uniform projection density in the unit triangle, but has a pitch, since it is a spiral. This pitch can produce artifacts in a refinement. The prop option generates nearly as uniform a distribution as spiral, but without this artifact.
For prop= Minalt is used for helical reconstructions to produce near side-views only. For example,
minalt=80 will produce projections ranging from side views to a 10 degree tilt.
EMAN Manual page, generated Tue May 25 14:15:52 2004