Compatibility with TrueGrid

James reads TrueGrid-style input and is not affiliated with TrueGrid or its publisher. A script that uses only the commands in the command reference runs in James without change, with the differences this chapter lists. Every other command of TrueGrid’s that James knows is either refused with a message naming it and the page of TrueGrid’s manual that documents it, or accepted and ignored because it only draws a picture or belongs to an interactive session; both sets are listed here in full. A word James does not know at all is reported as not a command it recognizes.

The posture

James reads a documented subset of TrueGrid’s language and runs it unchanged. Where TrueGrid imposes a limit for no reason James can find, James relaxes it. Where scripts rely on a quirk, James keeps the quirk. James does not copy TrueGrid bug for bug, and it does not promise that a mesh it writes matches TrueGrid’s node for node.

What runs unchanged

The commands in the command reference run as they do in TrueGrid, with the differences in the next section. A script that uses only those commands needs no change.

Known differences

Each item is a rule James applies. The command pages say more about the ones they concern.

• Picture commands are accepted and ignored. James draws nothing. Each command in the table “Commands accepted and ignored” discards the rest of its line and leaves no trace. rx, ry and rz are in that table and are also operators inside tr and tri; James reads them as operators there.
• interrupt, resume and caption do nothing. caption checks that its option is cap, on or off, and James raises E0217 otherwise.
• neutral selects James’s own format. TrueGrid’s neutral command writes TrueGrid’s neutral file. In James it selects James’s plain-text neutral file, which the neutral page describes. James accepts the command silently.
• comment and verbatim are read and discarded. The text they carry has nowhere to go in the two formats James writes. A verbatim block must still end with endverbatim (E1102).
• Two output formats. James writes neutral and Exodus II. Every other format selector is refused, and the table “Refused commands” lists them.
• Hex solids only. A negative entry in a block or cylinder list marks a shell partition, which James refuses (E0400). A 0 entry marks a gap, which James refuses too (E0413). Milestone M11 lifts both.
• Deeper nesting. include files nest to 32 levels where TrueGrid allows 19. when, for and while nest to 64 together, and if to 64, where TrueGrid documents 19 or 20.
• Wider numbers. An integer may reach 2147483647 in magnitude, where TrueGrid documents about 1e9. A real number may take any double-precision value, where TrueGrid documents a range of about 1e-18 to 1e18.
• An if closes in the file that opened it. An if opened in an include file and closed in the file that includes it raises E0319 in the first and E0300 in the second.
• The merge’s tie-break and zero rule. James visits nodes in the order of their numbers before the merge. Each node merges into the closest node that has already survived within the tolerance, and of two equally close survivors it takes the lower-numbered. A pair merges when its distance is less than the tolerance, so a tolerance of zero merges nothing. A chain of nodes each within tolerance of the next does not collapse to one node. The last tolerance command before a write governs alone.
• The merge report is printed after the file. A write that cannot open its file prints no report.
• The Exodus II layout. The file holds the coordinates, one HEX8 block per part and a QA record. It holds no node or element maps, no sets, no materials and no date.
• --format is a fallback. A format command in the script overrides the command-line flag.
• A second format command warns. A second neutral or exodusii that names a different format, before any write has used the first, raises E1104, and the later one governs. Repeating the same format is silent, and so is switching format after a write.
• A second title replaces the first, with no message.
• A part’s bad lists open it poisoned. A block or cylinder whose lists raise E0400, E0401, E0402, E0403 or E0413 still opens its part. James reads the commands that follow against corrected lists and the part adds nothing to the mesh. You see the one real error and not a row of phase errors after it.
• A repeated inline surface is a second surface. Two identical inline definitions in sf, sfi or ms make two surfaces. To reuse a surface, define it once with sd and refer to its number.
• sds takes a plain list. The list of surface numbers has no colon shorthand such as 1:4; James raises E0104.
• An angle past 360 degrees is kept, and converts periodically when the part ends. An mb or mbi offset may carry the angle of a cylinder part outside 0 to 360 degrees. James neither rejects nor reduces it. The part converts to Cartesian coordinates at endpart, so 390 degrees lands where 30 does.
• A part whose every element is deleted warns. James meshes it, writes none of its nodes unless you pass --write-unref-nodes, and prints a warning that names the flag.
• A part with no element is meshed, not refused. A list with one entry gives one node and no element in that direction. James meshes it, warns, and writes none of its nodes unless you pass --write-unref-nodes.
• The engine’s lines are capped at 4096. --engine-lines n raises the cap. A line before the summary says how many lines were not recorded and names the flag.
• Node caps. A part holds at most 100000000 nodes and one write at most 250000000. James stops with exit code 2 beyond either.
• Six surface kinds, two 3D curve types and three 2D segment kinds. sd builds plan, cy, sp, cone, crx/cry/crz and sds; every other type raises E1004 and every other inline type E0801. curd builds lp3 and csp3, one group per curve; every other type raises E0603. A 2D curve takes lp2, lar and lcc segments; every other raises E1009. Milestone M13 adds kinds.
• edge, patch, spp and nds are refused for want of what they need. nds needs a density function, which only the refused ndd makes (E0904). spp needs a template, which only the refused tmplt makes (E0804). edge and patch need a surface that has edges, and none of the surfaces James builds has one. Milestone M13 lifts all four.
• Five transformation operators are refused. tr and tri take thirteen operators; tf, ftf, rxy, ryz and rzx raise E0503. Milestone M14 reconsiders them.
• James does not reorder an inverted part. A part with negative Jacobians gets a warning per part, and its elements are written as they are. Milestone M9 reorders the corners of an inverted part.

Refused commands

James knows these 86 commands. It refuses 80 of them with E0100, and the message names the page of the original manual that documents the command. It reports the six equations x= to t3= as not recognized (E0105) in this version, so their message names no page. The tier says which part of the project’s plan the command belongs to, and the milestone says when it arrives. Milestones are plans, not promises; the changelog records what each version holds.

Command	Where it is documented	Tier	Milestone
tpara	Vol. 2, p. 478	long-term	long-term
bb	Vol. 1, pp. 379-384	near-term	M14
trbb	Vol. 1, pp. 394-395	near-term	M14
dom	Vol. 1, p. 277	near-term	M12
cycorsy	Vol. 1, p. 438	near-term	M11
neui	Vol. 1, p. 255	near-term	M10
unifmi	Vol. 1, p. 261	near-term	M10
blude	Vol. 2, p. 355	long-term	long-term
update	Vol. 1, p. 197	near-term	M12
orpt	Vol. 1, p. 196	near-term	M11
pbs	Vol. 1, pp. 202-203	long-term	long-term
ma	Vol. 1, pp. 207-208	near-term	M12
pa	Vol. 1, pp. 207-208	near-term	M12
relax	Vol. 1, pp. 238-240	near-term	M10
relaxi	Vol. 1, p. 240	near-term	M10
esm	Vol. 1, pp. 226-228	near-term	M10
esmp	Vol. 1, pp. 228-229	near-term	M10
tme	Vol. 1, pp. 247-252	near-term	M10
tmei	Vol. 1, p. 251	near-term	M10
unifm	Vol. 1, pp. 257-260	near-term	M10
neu	Vol. 1, p. 252	near-term	M10
hyr	Vol. 1, p. 229	near-term	M10
ssf	Vol. 1, p. 414	near-term	M11
ssfi	Vol. 1, p. 414	near-term	M11
tmplt	Vol. 1, p. 268	near-term	M13
accuracy	Vol. 2, p. 99	near-term	M13
npll	Vol. 2, p. 103	near-term	M13
project	Vol. 2, pp. 104-105	near-term	M13
ndd	Vol. 1, p. 275	near-term	M13
dndd	Vol. 1, p. 275	near-term	M13
apld	Vol. 2, p. 20	not classified	none scheduled
rlns	Vol. 2, p. 37	not classified	none scheduled
nerl	Vol. 2, pp. 433-434	near-term	M9 (its gate decides)
ptol	Vol. 2, pp. 452-457	near-term	M14
bptol	Vol. 2, pp. 452-457	near-term	M14
bnstol	Vol. 2, pp. 452-457	long-term	long-term
mns	Vol. 2, pp. 452-457	long-term	long-term
elvotest	Vol. 2, p. 486	long-term	long-term
epb	Vol. 2, pp. 486-487	long-term	long-term
ndigits	Vol. 2, pp. 486-487	long-term	long-term
npb	Vol. 2, pp. 486-487	long-term	long-term
save	Vol. 2, pp. 486-487	long-term	long-term
x=	Vol. 2, p. 459	near-term	M12 (E0105 today)
y=	Vol. 2, p. 459	near-term	M12 (E0105 today)
z=	Vol. 2, p. 459	near-term	M12 (E0105 today)
t1=	Vol. 2, p. 459	near-term	M12 (E0105 today)
t2=	Vol. 2, p. 459	near-term	M12 (E0105 today)
t3=	Vol. 2, p. 459	near-term	M12 (E0105 today)
abaqus	Vol. 2, pp. 489-494	near-term	M9
ale3d	Vol. 2, pp. 489-494	additional writers	none scheduled
ansys	Vol. 2, pp. 489-494	additional writers	none scheduled
autodyn	Vol. 2, pp. 489-494	additional writers	none scheduled
cf3d	Vol. 2, pp. 489-494	additional writers	none scheduled
cfd-ace	Vol. 2, pp. 489-494	additional writers	none scheduled
cfx	Vol. 2, pp. 489-494	additional writers	none scheduled
dyna3d	Vol. 2, pp. 489-494	near-term	M9
es3d	Vol. 2, pp. 489-494	additional writers	none scheduled
fidap	Vol. 2, pp. 489-494	additional writers	none scheduled
fluent	Vol. 2, pp. 489-494	additional writers	none scheduled
gemini	Vol. 2, pp. 489-494	additional writers	none scheduled
gridgen3d	Vol. 2, pp. 489-494	additional writers	none scheduled
iri	Vol. 2, pp. 489-494	additional writers	none scheduled
lsdyna	Vol. 2, pp. 489-494	near-term	M9
lsnike3d	Vol. 2, pp. 489-494	additional writers	none scheduled
icfep	Vol. 2, pp. 489-494	additional writers	none scheduled
kiva3v	Vol. 2, pp. 489-494	additional writers	none scheduled
kiva	Vol. 2, pp. 489-494	additional writers	none scheduled
marc	Vol. 2, pp. 489-494	additional writers	none scheduled
mpact	Vol. 2, pp. 489-494	additional writers	none scheduled
nastran	Vol. 2, pp. 489-494	additional writers	none scheduled
nike3d	Vol. 2, pp. 489-494	additional writers	none scheduled
enike3d	Vol. 2, pp. 489-494	additional writers	none scheduled
nnike3d	Vol. 2, pp. 489-494	additional writers	none scheduled
fnike3d	Vol. 2, pp. 489-494	additional writers	none scheduled
nekton2d	Vol. 2, pp. 489-494	additional writers	none scheduled
nekton3d	Vol. 2, pp. 489-494	additional writers	none scheduled
ne/nastran	Vol. 2, pp. 489-494	additional writers	none scheduled
refleqs	Vol. 2, pp. 489-494	additional writers	none scheduled
sap2000	Vol. 2, pp. 489-494	additional writers	none scheduled
starcd	Vol. 2, pp. 489-494	additional writers	none scheduled
plot3d	Vol. 2, pp. 489-494	additional writers	none scheduled
poly3d	Vol. 2, pp. 489-494	additional writers	none scheduled
tascflow	Vol. 2, pp. 489-494	additional writers	none scheduled
topaz3d	Vol. 2, pp. 489-494	additional writers	none scheduled
topaz3d2	Vol. 2, pp. 489-494	additional writers	none scheduled
viewpoint	Vol. 2, pp. 489-494	additional writers	none scheduled

The 35 format selectors the table marks “additional writers” have no milestone. The three that milestone M9 builds, lsdyna, abaqus and dyna3d, carry it. A format selector that is not in the table raises E0105, as does any other word James does not know.

Commands accepted and ignored

These 74 commands only draw a picture or steer an interactive session. James reads each one, discards the rest of its line, and prints nothing.

Command	What it draws
ad	the view and picture controls of the session
aad	the view and picture controls of the session
daad	the view and picture controls of the session
dad	the view and picture controls of the session
dads	the view and picture controls of the session
display	the view and picture controls of the session
disp	the view and picture controls of the session
draw	the view and picture controls of the session
grid	the view and picture controls of the session
pad	the view and picture controls of the session
poor	the view and picture controls of the session
postscript	the view and picture controls of the session
raad	the view and picture controls of the session
rad	the view and picture controls of the session
rindex	the view and picture controls of the session
sdint	the view and picture controls of the session
set	the view and picture controls of the session
slice	the view and picture controls of the session
triad	the view and picture controls of the session
tvv	the view and picture controls of the session
zclip	the view and picture controls of the session
l	the view and picture controls of the session
r	the view and picture controls of the session
u	the view and picture controls of the session
d	the view and picture controls of the session
rx	the view and picture controls of the session
ry	the view and picture controls of the session
rz	the view and picture controls of the session
trans	the view and picture controls of the session
fix	the view and picture controls of the session
unfix	the view and picture controls of the session
scale	the view and picture controls of the session
xscl	the view and picture controls of the session
yscl	the view and picture controls of the session
zscl	the view and picture controls of the session
zb	the view and picture controls of the session
zf	the view and picture controls of the session
angle	the view and picture controls of the session
reso	the view and picture controls of the session
restore	the view and picture controls of the session
center	the view and picture controls of the session
ibzone	picture controls (ibzone, noplot, plot)
noplot	picture controls (ibzone, noplot, plot)
plot	picture controls (ibzone, noplot, plot)
lcv	2D curve display
lv	2D curve display
lvi	2D curve display
lvs	2D curve display
dcd	3D curve display
dcds	3D curve display
dacd	3D curve display
acd	3D curve display
acds	3D curve display
rcd	3D curve display
rcds	3D curve display
racd	3D curve display
lacd	3D curve display
asd	surface display
asds	surface display
ansd	surface display
dasd	surface display
dsd	surface display
dsds	surface display
lasd	surface display
rasd	surface display
rsd	surface display
alv	CAD geometry display
dlv	CAD geometry display
dlvs	CAD geometry display
rlv	CAD geometry display
agrp	CAD geometry display
dgrp	CAD geometry display
dgrps	CAD geometry display
rgrp	CAD geometry display

The tiers

This is the plan, tier by tier, in the order James takes it up.

• Now. Hex solids, the commands in the command reference, merging under the four tolerance commands, and the neutral and Exodus II files.
• Near-term, one milestone at a time. M9 builds the LS-DYNA keyword, Abaqus and DYNA3D writers, with material numbers from mate, mt and mti and the reordering of an inverted part. M10 builds the smoothing commands relax, esm, tme and unifm, and whichever of their relatives its design gate takes. M11 builds shell partitions and shell elements with ssf, ssfi, orpt and gaps. M12 builds the coordinate equations with dom, update, ma and pa. M13 adds surface and curve kinds, then tmplt, ndd and dndd, which unblock edge, patch, spp and nds. M14 builds block boundaries, bb and trbb, with ptol and bptol.
• Long-term. Beams, IGES import, material properties, loads, boundary conditions and sets, and the commands that need them: blude, bnstol, mns and epb. Replication and transformation commands. Interactive mode, which pbs and the pt coordinate type need. The write options elvotest, ndigits, npb and save.

• Never. A graphical user interface, and bug-for-bug emulation of TrueGrid’s limits.

• Sources: TrueGrid User’s Manual v3.0.0, Vol. 1, pp. 196-197, 202-203, 207-208, 226-229, 238-240, 247-252, 255, 257-261, 268, 275, 277, 379-384, 394-395, 414, 438; Vol. 2, pp. 20, 37, 99, 103-105, 355, 433-434, 452-457, 459, 478, 486-487, 489-494