About VTP lines and hooks
Posted: Sat Oct 02, 2004 11:52 pm
Hello,
Here is an explanation about VTP hooks.
If, in the Australia folder, you open the file HL986450.BGL with the recent TmfViewer (the one dated 2004) and go to:
-37.560325
143.8270085
you can get the following picture. Look to the 3 views of the same line junction. They use different settings of the viewer.
On the top only the points are drawn. You will see the hooks. On the centre I asked TmfViewer to draw wide lines as polygons. On the bottom I asked TmfViewer to fill polygons.
You see that there is a starting hook and a ending hook. Points 1 and 2 and points N-1 and N are used to make the side of a triangle. Note that VTP lines are in fact polygons. Here is what I wrote recently on the AVSIM Scenery forum:
I think that any VTP line should have at least 4 points. Points 1 and 2 will generate the "true first" point and points N-1 and N will generate the "true last point". Based on TMFViewer display I assume that each midle point is internally translated to 2 points. I am using VTP Lines in SBuilder as follows:
1) I do not allow the width of the line to be greater than 255
2) I start the line with 2 points. These 2 points are perpendicular to the first line segment and their distance is the starting width of the line. The "mean position" of these 2 points is the position of the starting point of the source line.
3) I end lines with 2 points which are perpendicular to the last segment of the line. Again their distance is the width of the last point in the source line. The "mean position" of these 2 points is the position of the ending point of the source line.
4) I created an option in the VTP file import which I call "Remove Hooks". If this option (a check box) is set, Sbuilder imports 4 points lines as 2 points. If I do not set the option, Sbuilder import the points as if they all are different (as for example you see them in LWMViewer).
I suggest that you allways set this box.
Regards, Luis
Here is an explanation about VTP hooks.
If, in the Australia folder, you open the file HL986450.BGL with the recent TmfViewer (the one dated 2004) and go to:
-37.560325
143.8270085
you can get the following picture. Look to the 3 views of the same line junction. They use different settings of the viewer.
On the top only the points are drawn. You will see the hooks. On the centre I asked TmfViewer to draw wide lines as polygons. On the bottom I asked TmfViewer to fill polygons.
You see that there is a starting hook and a ending hook. Points 1 and 2 and points N-1 and N are used to make the side of a triangle. Note that VTP lines are in fact polygons. Here is what I wrote recently on the AVSIM Scenery forum:
I think that any VTP line should have at least 4 points. Points 1 and 2 will generate the "true first" point and points N-1 and N will generate the "true last point". Based on TMFViewer display I assume that each midle point is internally translated to 2 points. I am using VTP Lines in SBuilder as follows:
1) I do not allow the width of the line to be greater than 255
2) I start the line with 2 points. These 2 points are perpendicular to the first line segment and their distance is the starting width of the line. The "mean position" of these 2 points is the position of the starting point of the source line.
3) I end lines with 2 points which are perpendicular to the last segment of the line. Again their distance is the width of the last point in the source line. The "mean position" of these 2 points is the position of the ending point of the source line.
4) I created an option in the VTP file import which I call "Remove Hooks". If this option (a check box) is set, Sbuilder imports 4 points lines as 2 points. If I do not set the option, Sbuilder import the points as if they all are different (as for example you see them in LWMViewer).
I suggest that you allways set this box.
Regards, Luis