Huge memory consumption with about 33 million AIS_Point shown

Jason Tan
Tue, 05/07/2024 - 05:23

Forums:

Hello guys,
I have troubles with visualizing AIS_Point. I create about 0.33 million (330000) AIS_Point and use context->Load() to display them on screen, then I see a huge memory consumption (About 4.3 GB memory) and low frame rate. Could you please help me with this problem?

My point class:

 
class Point_3  : public AIS_Point {
public:
	Point_3(double x, double y, double z) :
		AIS_Point(new Geom_CartesianPoint(x, y, z))
	{
		point_index = 0;
	}
	~Point_3() {
	}
	unsigned int point_index;
	std::set<unsigned int> parent_poly_index;
};

How I add points to context (m_point is std::vector):

 
for (Handle(AIS_Point) point : m_point) {
     point->SetColor(Quantity_NOC_BLACK);
     point->Attributes()->SetDisplayMode(AIS_WireFrame);
     point->SetMarker(Aspect_TOM_BALL);
     m_context->Load(point, -1);
 }
m_context->DisplayAll();
m_view->FitAll();

gkv311 n
Tue, 05/07/2024 - 08:45

AIS_InteractiveObject(and it's subclass AIS_Point) is a complex object that has considerable memory overhead. It is not designed for displaying large amounts of such small objects like points.

For that purpose, it is better displaying points grouped into one or several interactive objects - using AIS_PointCloud or AIS_Shape classes.

P.S.: use code tags on the forum.

Jason Tan
Tue, 05/07/2024 - 10:53

Thanks for your reply! I read the tutorial about AIS presentation, maybe I need to create my own AIS class.
I'm trying to create an app to visualize solid mesh data with some interact functions, like selection with points, edges, solids. For example, points, edges,
and solids have their own index, I want to return their index when user selects them.
Right now, I want to derive SelectMgr_EntityOwner and add index to owner class, could you please give me some advice about doing this?

And, sorry for the format issue.

Jason Tan
Tue, 05/07/2024 - 11:21

I use Topods_Compound to create AIS_Shape. For each compound, I create 12 triangles, and these compound cost me about 10 GB memory. After I load them into context, memory used increase to 13 GB.

Function make_face construct Topods_Face and push_back to face(std::vector<Topods_Face>)

void polys_to_shapes(std::vector<Handle(OCC::Point_3)>& point_3s,
	std::vector<std::vector<unsigned int>>& polys, 
	std::vector<Handle(OCC::Edge)>& edges,
	std::vector< Handle(OCC::Polygon)>& polygons )
{
	static int edge_count = 0;
	std::map<std::pair<Handle(OCC::Point_3), Handle(OCC::Point_3)>, unsigned int> map;
	for (int i = 0; i < polys.size(); i++) {
		int size = polys[i].size();
		std::vector<Handle(OCC::Point_3)> points;
		if (size == 8) {                  // solid
			std::vector<TopoDS_Face> faces;
			for (int j = 0; j < 4; j++) {
				points.emplace_back(point_3s[polys[i][j]]);
			}
			points.emplace_back(point_3s[polys[i][0]]);
			make_shape(points, edges, map, faces);
			points.clear();

			for (int j = 4; j < polys[i].size(); j++) {
				points.emplace_back(point_3s[polys[i][j]]);
			}
			points.emplace_back(point_3s[polys[i][4]]);
			make_shape(points, edges, map, faces);
			points.clear();

			points.emplace_back(point_3s[polys[i][0]]);
			points.emplace_back(point_3s[polys[i][1]]);
			points.emplace_back(point_3s[polys[i][5]]);
			points.emplace_back(point_3s[polys[i][4]]);
			points.emplace_back(point_3s[polys[i][0]]);
			make_shape(points, edges, map, faces);
			points.clear();

			points.emplace_back(point_3s[polys[i][1]]);
			points.emplace_back(point_3s[polys[i][2]]);
			points.emplace_back(point_3s[polys[i][6]]);
			points.emplace_back(point_3s[polys[i][5]]);
			points.emplace_back(point_3s[polys[i][1]]);
			make_shape(points, edges, map, faces);
			points.clear();

			points.emplace_back(point_3s[polys[i][2]]);
			points.emplace_back(point_3s[polys[i][3]]);
			points.emplace_back(point_3s[polys[i][7]]);
			points.emplace_back(point_3s[polys[i][6]]);
			points.emplace_back(point_3s[polys[i][2]]);
			make_shape(points, edges, map, faces);
			points.clear();

			points.emplace_back(point_3s[polys[i][3]]);
			points.emplace_back(point_3s[polys[i][0]]);
			points.emplace_back(point_3s[polys[i][4]]);
			points.emplace_back(point_3s[polys[i][7]]);
			points.emplace_back(point_3s[polys[i][3]]);
			make_shape(points, edges, map, faces);
			points.clear();

			TopoDS_Compound compound;
			BRep_Builder builder;
			builder.MakeCompound(compound);
			for (auto& sh : faces) {
				builder.Add(compound, sh);
			}
			Handle(OCC::Polygon) p = new OCC::Polygon(compound);
			
			p->poly_index = i;
			//p->SetAttributes(nullptr);
			p->SetDynamicHilightAttributes(nullptr);
			p->SetHilightAttributes(nullptr);
			p->UnsetAttributes();
			polygons.emplace_back(p);
		}
		else if(size == 4) {                                // polygon
			for (int j = 0; j < size; j++) {
				points.emplace_back(point_3s[polys[i][j]]);
			}
			points.emplace_back(point_3s[polys[i][0]]);
			std::vector<TopoDS_Face> sh;
			make_shape(points, edges, map, sh);
			TopoDS_Compound compound;
			BRep_Builder builder;
			builder.MakeCompound(compound);
			builder.Add(compound, sh[0]);
			builder.Add(compound, sh[1]);
			Handle(OCC::Polygon) p = new OCC::Polygon(compound);
			p->SetDynamicHilightAttributes(nullptr);
			p->SetHilightAttributes(nullptr);
			p->poly_index = i;
			polygons.emplace_back(p);
		}

	}
}

Attachments:

screenshot-20240507-161617.png

gkv311 n
Tue, 05/07/2024 - 13:45

Puttings triangles and small polygons into TopoDS_Shape like this doesn't look like a good idea. It is better creating Poly_Triangulation or some custom structure for such data.

Jason Tan
Wed, 05/08/2024 - 04:21

Thank you for advice!