How to invoke the method ConvertFromSkp which are in the skp23ds.dll?

hDLL = LoadLibrary(L"skp23ds.dll");

lpfnDllFunc1 = (GetSketchUpModelExporterInterfaceFunc)GetProcAddress(hDLL,“GetSketchUpModelExporterInterface”);

sme = (SketchUpModelExporterInterface *)(lpfnDllFunc1());

sme->ShowOptionsDialog(false); //this statement can succeed

bool result = sme->ConvertFromSkp(input, output, NULL, NULL); //but this reuslt is false

int e = GetLastError();

Where does this "skp23ds.dll" file come from ?
(I do not see it included in the SketchUp SDK.)

EDIT: Okay, I found it.

The "Exporters/Skp23ds.dll" is one of SketchUp’s own native exporter libraries for use internally by SketchUp ONLY. It is not for use in 3rd party applications.

To cause SketchUp itself to export to a 3DS file we must use the Ruby API …

It can be invoked from a Ruby C extension that is running within SketchUp’s process.

Thank you very much!
I will try some other ways!

I would suggest that you need to use a C library for 3DS files along with the SketchUp file SDK.

Here is one I found just by doing a internet search … (but the last change was 4 years ago.)