【转帖】correct use of extended entity data
 

correct use of extended entity data
correct use of extended entity data
can you help me with this?
i am creating 2d polylines, eg:
code:
oddbblocktablerecordptr pblock;
// open the block for adding objects
pblock = idblock.safeopenobject( oddb::kforwrite );
// polyline header
oddb2dpolylineptr ppoly = oddb2dpolyline::createobject();
pblock->appendoddbentity( ppoly );
ppoly->setlayer( idlayer );
...
now, i create an outer polyline and then i create some inner polylines. these inner polylines are considered as "holes" to the outer polyline.
what i would like to do is use extended entity data to indicate that these inner polylines are "holes".
you see, they are on the same layer as the outer polyline (for legacy code reasons) and thus, when i do my post processing in autocad, it will be harder to ascertain which polylines are holes. but if they had extended entity data saying they were holes it would be easy.
cany you help me?
andrew
a closed area with holes in autocad can be represented by solid hatch entity, by region...
it's possible to use extended data to store any information you want but autocad itself does not know anything about your own extended data.
sergey slezkin
quote:
originally posted by sergey slezkin
a closed area with holes in autocad can be represented by solid hatch entity, by region...
it's possible to use extended data to store any information you want but autocad itself does not know anything about your own extended data.
i already have generated them as solid hatch objects. i need this for area calculations. but you have given me an idea...
sergey
i think i might have been looking at this the wrong way. i was trying to achieve what i wanted via an external vba macroi but i now wonder if i can do this in my master dwg direct application.
this is what i create in the drawing:
master outer polyline
unspecified inner poylines.
hatch object (using the aforementioned outer/inner polylines).
now, i am sure i could easily modify my code to give me an "area" for the hatch. is there anyway using dwg direct that i can calculate the outer polyline area and subtract the innser polyline areas from it and it give me back the answer?
currently dd does not have area calculation functionality inside it. but if your polylines do not have bulges (contain only line segments) it's rather simple task...
sergey slezkin