For a complete introduction see those links and the Creo Parametric included API documentation and examples:
[Knowledge Hub] Creo Parametric - Customization
https://www.ptc.com/en/support/article/CS318231
Creo Object TOOLKIT C++ Help Center
https://support.ptc.com/help/creo_toolkit/otk_cpp_pma/r11.0/usascii/
Shipped with every Creo Parametric (select optional API during Creo setup):
OTK:
<Creo Common Files>\otk_cpp_doc\
- "Getting started Guide" (PDF)
- "Release Notes" (PDF)
- "User's Guide" (PDF/HTML)
<Creo Common Files>\otk_cpp_doc\objecttoolkit_Creo\
- "API Wizard"
C TOOLKIT:
<Creo Common Files>\protoolkit\
- "Getting started Guide" (PDF)
- "Release Notes" (PDF)
- "User's Guide" (PDF/HTML)
<Creo Common Files>\protoolkit\protkdoc\
- "API Wizard"
"Release Notes" (RelNotes): important information for each Creo release (new/deprecated/dropped functions)
"User's Guide" (OTKUG/TKUSE): detailed description on API topics; they complement each other – use both!
"API Wizard": function/class listing with function/method details (in/out) and links to examples (if existing)
💡Examples: source code and make files:
<Creo Common Files>\protoolkit\protk_appls\
<Creo Common Files>\otk\otk_cpp\
For OTK & OTK Java & TOOLKIT: Creo UI Editor
<Creo Common Files>\applications\creouieditor\otk_cpp_doc\creo_uifc_ug.pdf
- "Creo User Interface Foundation Classes User Guide"