Base regions¶
Commands of the base_regions chapter of the database, 11 entries. The status words are defined once, on the compatibility matrix, which says what each rests on and what the script builder does with it. Read it before this page: broken and removed are refusals, so a row here can be telling you the emitter will not write that command for that version.
AUTO_DETECT_BASE_REGIONS¶
Phase setup, layout bare. Manual: SRC-003 p.317.
Marks every base region the detector finds over the whole geometry, using the bending angle above. Takes nothing, so which boundaries it marks is not something the script chooses.
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.274, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.312, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.316, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.317 |
| 26.121 | documented | SRC-740 p.320, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
CREATE_NEW_BASE_REGION¶
Phase setup, layout inline. Manual: SRC-003 p.317.
Marks one mesh boundary as a base region and gives it a pressure model. No all-form is stated, so -1 is not accepted here; AUTO_DETECT_BASE_REGIONS is the command that marks several at once. THE HEADING AND THE TABLE NAME THE SECOND ARGUMENT DIFFERENTLY, BASE_TYPE against BASE_MODEL, in the four editions read then. The table's spelling is used because it is the one that carries the values, and because the sibling SET_BASE_REGION_CP's table spells it BASE_MODEL too, so the two commands agree under that reading and disagree under the other. CUSTOM IS ACCEPTED HERE TOO, AND THE MANUAL DOES NOT SAY SO. This page lists three models and the sibling setter lists CUSTOM where this one lists USER; a 2026-08-08 probe found this command taking EITHER word and the setter taking CUSTOM alone (RPT-021). So the two vocabularies really do differ, the manual is right about the setter and incomplete about this one, and the fourth token is recorded from the measurement. The manual states that CP is ignored under the EMPIRICAL model. It is still required here, because this command's own sample passes three arguments and no edition prints a two-argument form of it; contrast SET_BASE_REGION_CP below, where a two-argument sample IS printed and the argument is optional in consequence.
| Argument | Specification |
|---|---|
surface_index |
int |
base_model |
enum in |
cp |
float |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.274, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.312, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.316, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.317 |
| 26.121 | documented | SRC-740 p.320, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
DELETE_BASE_REGION¶
Phase setup, layout inline. Manual: SRC-003 p.317.
Unmarks one base region. NO ALL-FORM IS STATED HERE, unlike the two neighbouring commands that take the same kind of index and document -1. Recorded as stated: the two neighbours prove the manual says so when it means it, which makes the silence here evidence rather than an omission to be filled in by analogy.
| Argument | Specification |
|---|---|
base_region_boundary |
int |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.274, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.312, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.316, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.317 |
| 26.121 | documented | SRC-740 p.320, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
DETECT_BASE_REGIONS_BY_SURFACE¶
Phase setup, layout inline. Manual: SRC-003 p.317.
The same detection restricted to one mesh boundary, for a geometry where the whole-model form marks more than intended. The manual states the index must be greater than zero and no all-form, so -1 is not accepted.
| Argument | Specification |
|---|---|
boundary_index |
int |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.274, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.312, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.316, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.317 |
| 26.121 | documented | SRC-740 p.320, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
REMESH_BASE_REGION¶
Phase geometry, layout keyword_block. Manual: SRC-003 p.318.
Rebuilds a base region's faces as a radial distribution, which a detected base region does not have: it inherits whatever the import gave it. Phase is geometry, this being the one command in the chapter that changes the mesh rather than labelling it. GROWTH_SCHEME IS SPELLED AS A NUMBER HERE AND AS A WORD EVERYWHERE ELSE. 1 is successive and 2 is dual-sided, while the three CCS chapters spell the same two schemes SUCCESSIVE and DUAL-SIDED. The numbers are recorded because they are what this page prints, and the closed set is stated so passing the word is refused rather than written into a script the solver will not read. INNER_RADIUS takes 0.0 for no inner radius, which the manual states and which is worth reading as a documented value rather than as an edge case.
| Argument | Specification |
|---|---|
base_region |
int |
inner_radius |
float [simulation length units] |
elements |
int |
growth_scheme |
enum in |
growth_rate |
float |
| Version | Status | Evidence |
|---|---|---|
| 26.100 | documented | SRC-741 p.313, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.317, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.318 |
| 26.121 | documented | SRC-740 p.321, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.322, unchanged from SRC-750 p.322 |
| 26.124 | documented | SRC-752 p.322, the SRC-751 file, carried from 26.123; not run on 26.124 |
SELECT_BASE_REGION_FACES¶
Phase setup, layout inline. Manual: SRC-003 p.318.
Selects the mesh faces of a base region, or of all of them with -1, which the sample passes. Selection is application state rather than a solver input; what reads it is the commands that act on a selection.
| Argument | Specification |
|---|---|
base_index |
int |
| Version | Status | Evidence |
|---|---|---|
| 25.100 | documented | SRC-748 p.292, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.291, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.313, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.317, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.318 |
| 26.121 | documented | SRC-740 p.321, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.322, unchanged from SRC-750 p.322 |
| 26.124 | documented | SRC-752 p.322, the SRC-751 file, carried from 26.123; not run on 26.124 |
SET_BASE_REGION_BENDING_ANGLE¶
Phase setup, layout inline. Manual: SRC-003 p.284.
Threshold on how far a surface may bend away from the aft-facing direction and still be detected as part of a base region, which is what AUTO_DETECT_BASE_REGIONS and DETECT_BASE_REGIONS_BY_SURFACE read. DOCUMENTED ON TWO PAGES, AND ONLY ONE OF THEM SAYS ANYTHING. This chapter prints the signature heading and nothing beneath it, while p.284 gives the command a parameter table, a stated range and a sample passing a value. The p.284 entry is what is recorded. The empty heading is not read as a bare command, because the rule for that shape is that nothing in the manual contradicts it, and here the same manual does. The manual bounds the angle between 0 and 90 degrees. The bound is NOT enforced, which is the standing treatment of the manual's stated bounds in this database (design decision of 2026-08-08); the argument's own page is where a reader finds it, and this note is where a reader of the database does.
| Argument | Specification |
|---|---|
angle |
float [deg] |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.255, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.274, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.273, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.278, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.283, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.284 |
| 26.121 | documented | SRC-740 p.287, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.288, unchanged from SRC-750 p.288 |
| 26.124 | documented | SRC-752 p.288, the SRC-751 file, carried from 26.123; not run on 26.124 |
SET_BASE_REGION_CP¶
Phase setup, layout inline. Manual: SRC-003 pp.317-318.
Changes the pressure model of a base region that already exists. THE USER-SPECIFIED MODEL IS SPELLED CUSTOM HERE AND USER ON CREATE_NEW_BASE_REGION, two commands apart on the same page, in all four editions. MEASURED 2026-08-08 (RPT-021): this command takes CUSTOM and REFUSES USER, while the creator takes either. So the asymmetry is real rather than a documentation slip, and this entry's three tokens are now a measurement instead of a reading. The creator gained CUSTOM from the same run. CP IS OPTIONAL, and unusually the manual proves it rather than stating it: the page prints TWO samples for this command, one passing a value under CUSTOM and one passing only the model under EMPIRICAL. That is a sample settling an arity question instead of contradicting it, which is rare enough in this manual to record. The table's description of BASE INDEX is copied from DELETE_BASE_REGION and describes the index as the one to be deleted; the same copy appears on SELECT_BASE_REGION_FACES. Cosmetic, and noted only so a reader comparing the pages does not take it for a statement about what the command does.
| Argument | Specification |
|---|---|
base_index |
int |
base_model |
enum in |
cp |
float (optional) |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.275, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 pp.312-313, same grammar as 26.120 |
| 26.101 | documented | SRC-725 pp.316-317, same grammar as 26.120 |
| 26.120 | documented | SRC-003 pp.317-318 |
| 26.121 | documented | SRC-740 pp.320-321, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
SET_BASE_REGION_TRAILING_EDGES¶
Phase setup, layout inline. Manual: SRC-003 p.317.
Marks the rim of a base region as a trailing edge, which is what lets the wake leave the body there. The manual documents -1 for every base region, and the sample passes it. The -1 is in this note rather than declared as an all_sentinel because base regions are not an inventory the script builder tracks: with no kind to resolve, nothing would read the declaration.
| Argument | Specification |
|---|---|
base_region_boundary |
int |
| Version | Status | Evidence |
|---|---|---|
| 25.000 | documented | SRC-749 p.274, same grammar as 26.120 |
| 25.100 | documented | SRC-748 p.291, same grammar as 26.120 |
| 26.000 | documented | SRC-747 p.290, same grammar as 26.120 |
| 26.100 | documented | SRC-741 p.312, same grammar as 26.120 |
| 26.101 | documented | SRC-725 p.316, same grammar as 26.120 |
| 26.120 | documented | SRC-003 p.317 |
| 26.121 | documented | SRC-740 p.320, same grammar as 26.120 |
| 26.123 | documented | SRC-751 p.321, unchanged from SRC-750 p.321 |
| 26.124 | documented | SRC-752 p.321, the SRC-751 file, carried from 26.123; not run on 26.124 |
SET_OUTFLOW_TRAILING_EDGES¶
Phase setup, layout inline. Manual: SRC-750 p.331.
Marks the trailing edges of a base region as outflow edges, which is how a jet or duct exit gets a wake that leaves the body instead of one that closes behind it. First documented by the 26.122 edition. A value of -1 selects every base region. Its parameter table names the row after the command itself rather than after the argument, which is a formatting slip on that page and not a second call form: the signature and the sample both carry one value. RENAMED AFTER A DOCUMENTED LIFETIME OF EXACTLY ONE BUILD. The 26.123 edition prints SET_OUTLET_TRAILING_EDGES on the same page, with the same single argument, the same all-form value and the same sample, and this spelling appears nowhere in it. The successor is a separate entry rather than an alias field on this one: an alias would have to say which editions it holds for, and a per-name version block is what this database already has for saying that. No transitional spelling is documented, so a script written for 26.122 stops working on the build issued after it.
| Argument | Specification |
|---|---|
base_region_boundary |
int |
| Version | Status | Evidence |
|---|---|---|
| 26.122 | documented | SRC-750 p.331, the first edition to document it |
| 26.123 | removed | SRC-751 p.331 prints SET_OUTLET_TRAILING_EDGES in this command's place, in the chapter body and in the Script Index alike, and this spelling appears nowhere in that edition. A count over the document rather than a statement about the solver: no run on this build has tried either name.; Successor: SET_OUTLET_TRAILING_EDGES |
| 26.124 | removed | SRC-752 p.331, the SRC-751 file, carried from 26.123; not run on 26.124; Successor: SET_OUTLET_TRAILING_EDGES |
SET_OUTLET_TRAILING_EDGES¶
Phase setup, layout inline. Manual: SRC-751 p.331.
Marks the trailing edges of a base region as outlet edges. The 26.123 spelling of what the 26.122 edition calls SET_OUTFLOW_TRAILING_EDGES, and nothing else about it moves: same page, same single base region boundary index, same -1 for every base region, same printed sample. IT TAKES A BASE REGION AND NOT AN OUTLET, which the name invites a reader to get wrong. The argument is the index of a base region boundary, exactly as its predecessor's was; the outlet perimeter marking documented in the same edition's user-interface chapter is a different feature with no command in the scripting reference at all, and the two are not linked on any page. Its parameter table carries the same formatting slip as its predecessor's, naming the row after the command rather than after the argument.
| Argument | Specification |
|---|---|
base_region_boundary |
int |
| Version | Status | Evidence |
|---|---|---|
| 26.123 | documented | SRC-751 p.331, the first edition to print this spelling |
| 26.124 | documented | SRC-752 p.331, the SRC-751 file, carried from 26.123; not run on 26.124 |