topic Re: Functions to help find overlapping objects in Archicad C++ API

Functions to help find overlapping objects

Anonymous — Tue, 04 Oct 2022 14:32:17 GMT

Hello guys,

I have to find out if two object elements are overlapping. Are there any functions that can return something that would help me - for example object boundary position or whatever else?

The only one that I found helpful so far is ACAPI_Element_GetHotspots and if there is no easier way I am going to get the boundary hotspots of the objects and think of some algorithm to calculate the objects positions and if they are overlapping. The objects are made and imported by myself so I can put hotspots wherever I want (I think).

Re: Functions to help find overlapping objects

dfintha — Mon, 20 May 2019 13:45:27 GMT

Hello,

You can use the APIDb_CalcBoundsID functionality of ACAPI_Database to get a bounding box of the 3D extent of your object.

Best regards,
Dénes

Re: Functions to help find overlapping objects

Tibor Lorantfy — Tue, 21 May 2019 06:38:02 GMT

Hi,

You can use ACAPI_Element_GetCollisions to detect collisions between elements (this function is available from API 21).
Here is an example from the Element_Test example Add-On, it detects the collisions between the selected elements:

void	Do_DetectCollisionsBasedOnSelection (void)
{
	API_SelectionInfo 	selectionInfo;
	API_Neig**			selNeig;
	GSErrCode			err;

	// Get selection
	err = ACAPI_Selection_Get (&selectionInfo, &selNeig, true);
	BMKillHandle ((GSHandle *) &selectionInfo.marquee.coords);

	if (err != NoError && err != APIERR_NOSEL) {
		BMKillHandle ((GSHandle *) &selNeig);
		ErrorBeep ("ACAPI_Selection_GetInfo", err);
		return;
	}

	if (err == APIERR_NOSEL || selectionInfo.typeID == API_SelEmpty) {
		WriteReport_Alert ("No selected elements");
		return;
	}

	GS::Array<API_Guid> guidList1, guidList2;
	GS::Array<GS::Pair<API_CollisionElem, API_CollisionElem>> collisions;

	for (Int32 i = 0; i < selectionInfo.sel_nElemEdit; i++) {
		guidList1.Push ((*selNeig).guid);
		guidList2.Push ((*selNeig).guid);
	}
	BMKillHandle ((GSHandle *) &selNeig);

	// Detect collisions
	API_CollisionDetectionSettings colDetSettings;
	colDetSettings.volumeTolerance = 0.0001;
	colDetSettings.performSurfaceCheck = true;
	colDetSettings.surfaceTolerance = 0.0001;
	err = ACAPI_Element_GetCollisions (guidList1, guidList2, collisions, colDetSettings);
	Do_DumpCollisions (collisions);
}

Regards,
Tibor

Re: Functions to help find overlapping objects

Anonymous — Wed, 22 May 2019 08:32:42 GMT

Wonderful! Thank you both! I think I will combine both your methods!

Re: Functions to help find overlapping objects

Anonymous — Thu, 23 May 2019 11:29:36 GMT

Wow!
ACAPI_Element_GetCollisions needs 1 to 3 minutes to return - 3 elements with 3 collisions.
My CPU is 100%, MacBook Pro 2017!
Is it possible?

Re: Functions to help find overlapping objects

Tibor Lorantfy — Fri, 24 May 2019 07:53:05 GMT

n.mihaylov wrote:
ACAPI_Element_GetCollisions needs 1 to 3 minutes to return - 3 elements with 3 collisions.

How many elements do you input to ACAPI_Element_GetCollisions function? All elements from your project?

Re: Functions to help find overlapping objects

Anonymous — Mon, 27 May 2019 06:18:05 GMT

I check every time and I have only 3 elements in guidList1 and guidList2:

ACAPI_Element_GetCollisions (guidList1, guidList2, collisions, colDetSettings);