FROM
- Last UpdatedOct 06, 2022
- 2 minute read
In some cases we require an offset from a fixed point, other than the position of an item. For example, a point or attribute.
The FROM syntax is used for this. We may still use WRT in combination with FROM, but in this case the WRT is only used to determine the axis direction and not the offset, since the offset is specified by the FROM part.
Consider the following:
|
Item |
Comments |
|---|---|
|
A SITE at (0,0,0) |
With default (World) orientation. |
|
A ZONE at (100,0,0) |
With default (World) orientation. |
|
An EQUIPMENT at (100,0,0) |
With orientation ’N IS E. |
|
A BOX at (-100,0,0) |
With default (World) orientation. |
The result of Q (N 100 WRT /* FROM /BOX1), shown as Ä, will depend on the current element.
|
Location |
Result |
|---|---|
|
World, Site, and Zone |
(200,200,0) since the offset of N100 is applied in world axis rather than /BOX1 axis. |
|
Equipment |
(100,200,0). Note: |
|
Box |
(200,0,0), because the default axis for the result is the Equipment. |
The result of ’Q (N 100 WRT /BOX1 FROM /* ) is different:
|
Location |
Result |
|---|---|
|
Site and Zone |
(100,0,0) |
|
Equipment |
(0,0,0) |
|
Box |
(0, -100, 0), because the axis for the result is the Equipment. |
The result of ’Q (N 100 FROM /* )’ is different again.
For this we cannot mark an absolute point on the diagram since the default WRT will vary with the current element. In fact, for the SITE, ZONE, EQUI the point Ä is marked, and for the BOX the point coincides with the ZONE.
|
Location |
Result |
|---|---|
|
Site and Zone |
(0,100,0) |
|
Equipment |
(-100,100,0), because the default result axis is the Zone. |
|
Box |
(0, -100, 0), because the axis for the result is the Equipment. |