Dear IMP,

I'm trying to figure out how one would use the IDEAL_HELIX representation for purposes of EMRestraint.

I'm working with the tutorial example and the representation looks like this:

m = IMP.Model()
representation = IMP.pmi.representation.Representation(m,upperharmonic=True,disorderedlength=False)

# compname       hier_name   color    fastafile                    fastaid    pdbname                        chain     resrange     read beadsize rigid_body super_rigid_body emnum_components, emtxtfilename    emmrcfilename
domains=[("Rpb1",  "Rpb1_1",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:A",  datadir+"1WCM_map_fitted.pdb",   "A",   (1,1140,0),    True,  20,  None,  None,  57,  None,  None,  None),
         ("Rpb1",  "Rpb1_2",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:A",  datadir+"1WCM_map_fitted.pdb",   "A",   (1141,1274,0), True,  20,  None,  None,   7,  None,  None,  None),
         ("Rpb1",  "Rpb1_3",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:A",  datadir+"1WCM_map_fitted.pdb",   "A",   (1275,1455,0), True,  20,  None,  None,   9,  None,  None,  None),
         ("Rpb2",  "Rpb2_1",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:B",  datadir+"1WCM_map_fitted.pdb",   "B",   (1,1102,0),    True,  20,  None,  None,  55,  None,  None,  None),
         ("Rpb2",  "Rpb2_2",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:B",  datadir+"1WCM_map_fitted.pdb",   "B",   (1103,-1,0),   True,  20,  None,  None,   6,  None,  None,  None),
         ("Rpb3",  "Rpb3",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:C",  datadir+"1WCM_map_fitted.pdb",   "C",   (1,-1,0),      True,  20,  None,  None,  16,  None,  None,  None),
         ("Rpb4",  "Rpb4_1",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:D",                        "BEADS",  None,   (1,54,0),      True,  20,     1,   [1],   0,  None,  None,   [1]),
         ("Rpb4",  "Rpb4_2",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:D",                  "IDEAL_HELIX",  None,  (55,75,0),      True,   1,     1,   [1],  20,  None,  None,   [1]),
         ("Rpb4",  "Rpb4_3",  0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:D",                        "BEADS",  None,  (76,-1,0),      True,  20,     1,   [1],   0,  None,  None,   [1]),
         ("Rpb5",  "Rpb5",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:E",  datadir+"1WCM_map_fitted.pdb",   "E",   (1,-1,0),      True,  20,  None,  None,  11,  None,  None,  None),
         ("Rpb6",  "Rpb6",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:F",  datadir+"1WCM_map_fitted.pdb",   "F",   (1,-1,0),      True,  20,  None,  None,   8,  None,  None,  None),
         ("Rpb7",  "Rpb7",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:G",                        "BEADS",  None,   (1,-1,0),      True,  20,     4,   [4],   0,  None,  None,   [4]),
         ("Rpb8",  "Rpb8",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:H",  datadir+"1WCM_map_fitted.pdb",   "H",   (1,-1,0),      True,  20,  None,  None,   7,  None,  None,  None),
         ("Rpb9",  "Rpb9",    0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:I",  datadir+"1WCM_map_fitted.pdb",   "I",   (1,-1,0),      True,  20,  None,  None,   6,  None,  None,  None),
         ("Rpb10", "Rpb10",   0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:J",  datadir+"1WCM_map_fitted.pdb",   "J",   (1,-1,0),      True,  20,  None,  None,   4,  None,  None,  None),
         ("Rpb11", "Rpb11",   0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:K",  datadir+"1WCM_map_fitted.pdb",   "K",   (1,-1,0),      True,  20,  None,  None,   6,  None,  None,  None),
         ("Rpb12", "Rpb12",   0.00,  datadir+"1WCM_new.fasta.txt",  "1WCM:L",  datadir+"1WCM_map_fitted.pdb",   "L",   (1,-1,0),      True,  20,  None,  None,   4,  None,  None,  None)]


bm1 = IMP.pmi.macros.BuildModel1(representation)
bm1.build_model(domains)


When I was modeling Rpb4 and Rpb7 as BEADS, everything seemed to be working.  I then tried modeling a stretch of Rpb4 as IDEAL_HELIX, but I'm not sure the density of that helix is recognized and the representation/density doesn't look they way I would expect in Chimera.  I thought I should have it represented by 1 bead/aa.  I basically just want to model it as a straight tube both for representational and EM density purposes. 

Thanks much,
Julian