There are two methods to select boundaries when using Hatch in CAD: Pick Points and Select Objects. Many people can’t tell the difference and most of them choose Pick Points.
So when to use Pick Points and when to use Select Objects? I made a simple comparison using a couple of examples, I guess you’ll have some idea after reading this.
The above are cases in which the Pick Points method has clearly specify the area to be hatched, it’s very easy and applies to most cases; Select Objects are relatively more demanding: for the boundary, closed polyline is better, if not a
From the picture above, we can see that in some cases, the Pick Points method has the same effect as the Select Objects method while in other cases, we need to ignore other line in the closed polyline and directly point selecting polyline is inevitably the best option.
Using which method to hatch requires knowing the effect of the two methods in a different situation and the calculation method of the two methods. When using the Pick Points method to select an area to hatch, the CAD software will search and calculate within the viewport and will generate a reasonable range. When there are many graphics in the viewport and if the graphics are complex, for example, there are many circles, arc, spline and there are also many intersections, nest, slowing the calculation process. In the lower version of CAD, it asks you whether to continue for there are many objects and heavy calculation burden.