From Tekla to the saw: what an NC file carries, and what it leaves behind
Contents — 7 sections
The DSTV import is the shortest path from a detailing model to a cutting plan. Point KRON at a folder of NC files and it recognises the parts automatically, with no schedule to retype, no transcription errors and no argument about whether the list matches the model.
It is also the feature most likely to give you a result that looks correct and is not. The import itself is reliable enough; the difficulty is that a standard NC file does not contain everything KRON needs, and both of the missing pieces fail quietly.
DSTV import is not available on every plan, and neither is STEP/IGS. The comparison matrix says which tier carries which import.
What KRON reads
For each part in an NC file, KRON recognises the geometry including the shape of both end cuts, the profile designation, the material, the cut angles, and the holes, cut-outs and part connections used to derive splice restrictions.
That is a substantial amount of engineering data arriving without anyone typing it, and the import is genuinely quick. Reading the files is the slow part, not interpreting them.
What it does not
The standard. A standard Tekla export writes geometry, not the catalogue the profile belongs to. This is the commonest source of confusion with the import and it produces a specific symptom: parts arrive with their standard shown as non-standard.
What KRON does instead is match the geometry against the standards catalogues you have ticked in the Standards Manager, so the fix is not in Tekla. It is in KRON, before you import.
standards-managerThe Standards Manager with several catalogues ticked.
Where: Either module → the book icon at the bottom of the left-hand rail.
Must show: The list of available standards, the select-all-by-country button at the top, and the Save button.
The order matters more than it appears to:
- Open the Standards Manager and tick the catalogues you actually work with.
- Delete any parts you have already imported.
- Import them again.
Ticking a catalogue does not retroactively re-match parts already in the project, which is what makes the delete step necessary and what makes it worth getting the catalogues right before a large import rather than after.
A second-order version of the same problem exists. Where several selected standards describe profiles with identical characteristics, KRON takes the first match. If it picks the wrong one, disable the standard you do not need instead of correcting parts one at a time.
Part connection data, unless you asked for it. The automatic part-connection splice restriction, which stops KRON putting a weld where another member frames in, depends on connection information being written into the NC files, and a default Tekla export does not always include it.
This is the failure to be most careful about, because nothing reports it. Export without those settings, switch the restriction on in KRON, and the import succeeds while the restriction has nothing to act on. What you get is a plan with splices in places you believed you had ruled out. If part connections matter to you, verify on a small test export before committing a whole project.
Three decisions before you export
Decide what a single export contains. KRON nests everything you give it together, so an export containing more parts of the same profile and material gives the optimiser more to work with and produces a tighter plan. Exporting one small assembly at a time is the commonest reason a shop sees disappointing results and concludes the optimiser is weak; in most of those cases it was handed four parts and asked to work miracles.
Enable the settings that expose part connections if you intend to use that restriction, per above.
Know your encoding. Tekla writes NC files in different encodings depending on version and locale. KRON asks at import time and the selector carries hints: UTF-8 covers Tekla 2016 and later, Advance Steel and most modern software, while older exports are usually a legacy single-byte encoding.
Get this wrong and profile or material names arrive garbled. Recovery means deleting the added parts and profiles, then importing again with the correct encoding, because there is no way to fix the encoding after the fact. Check it on the first few parts of a large import rather than at the end.
The import itself
The button is the file icon labelled dstv, under Production → Adding Parts. Select the drawing set first or it stays inactive.
At import you choose the encoding, then set the splice constraints to derive from the files. There are five, each with its own measurement:
- forbid splicing in hole zones, with a constraint length in millimetres
- forbid splicing in part connection zones, with a constraint length in millimetres
- forbid splicing in part cut-out zones, with a constraint length in millimetres
- no splice at the ends of the part, as a percentage of length
- forbid splicing in the centre of the part, as a percentage of length
There is no need to reason about these colliding. Overlapping zones are merged automatically, so switch on everything that genuinely applies instead of working out which restriction subsumes which.
dstv-import-dialogThe Add Parts using DSTV dialog.
Where: Production → Adding Parts → the file icon labelled dstv.
Must show: The File Encoding selector with its Tekla-version hint, all five Splice Constraints toggles with their constraint-length fields, and the Select Files button.
KRON adds the profiles and materials it finds to the drawing set as it goes. A large set takes a while.
Four things to check afterwards
The failures list. Parts that could not be loaded are listed with the reason. Read it instead of dismissing it: a systematic failure usually points at an export setting, and finding that on part three is cheaper than finding it on part three hundred.
The names, for garbling. The encoding is not fixable after the fact, so the sooner you catch it the less there is to delete.
Duplicates. If a part with the same name has already been loaded, KRON appends the date and time of the repeat load to the name instead of overwriting the original. Silently replacing a part somebody may already have cut would be worse, but it does mean re-importing the same files leaves you with two copies to clean up.
What is now locked. Parts imported from DSTV cannot be edited in KRON. They are bound to their source file so the two cannot diverge, and only splice restrictions remain editable. Where the geometry is wrong, the fix is in Tekla followed by a re-import. That rule frustrates people until the first time it saves them, since a cutting plan that disagrees with the detailing model produces parts nobody can install.
Symptoms and causes
| Symptom | Likely cause |
|---|---|
| Profiles show as non-standard | The relevant catalogue is not ticked in the Standards Manager. Tick it, delete the parts, re-import. |
| The wrong standard was chosen | Two catalogues describe the same geometry. Disable the one you do not use. |
| Garbled profile or material names | Wrong encoding at import. Delete parts and profiles, re-import. |
| Part connection restrictions have no effect | The connection information was not written during the Tekla export. |
| Nothing imports at all | Check the failures list, where the reason is reported per file. |
If you are not on Tekla
DSTV is a standard rather than a Tekla format. Anything that writes it, Advance Steel included, imports the same way, and the encoding hint in the selector covers those cases too.
For solid geometry instead of NC, KRON also recognises parts from STEP and IGS files. Neither format carries quantity or material, so after recognition a Recognised Parts window opens for you to supply both, and from there the parts behave like any others. Note that STP support covers a part, not an assembly.