The Post Base is a rectangular base plate for a post or column: a plain rectangle with four bolt holes in a 2 x 2 pattern and a circle for the post at the centre of the hole pattern. By default it is a square plate with one bolt hole towards each corner. It is the Rect with 4 holes shape with the post circle added, and it has the same hole properties.
It appears in the shapes library under Rectangular Shapes and Gussets.
Post Base in PrimeShape: the property page (left) and the shape with its dimensions (right).
Insert point and orientation
The insert point is the bottom left corner of the plate. Width is built to the right along X and Height upwards along Y. The bolt hole pattern is centred on the plate: with both offsets at 0 the middle of the pattern, and the centre of the post circle, are at (Width / 2, Height / 2) from the insert point. Hole Offset X and Hole Offset Y are added to that position and move the holes and the post circle together.
A new Post Base has two columns and two rows of holes. Num. of Cols and Num. of Rows change the count; the pattern stays centred on the plate and the post circle stays at the centre of the pattern. The hole centres are Horiz. Pitch apart across the plate and Vert. Pitch apart up it.
Properties
Lengths are in the current units (mm or inches). The defaults shown are for a new shape; the inch defaults are used when the program is set to inches. The table follows the order of the property page. Post D is the last property on the page, below the Polar Array group.
Property |
Description |
Default |
Width |
Overall width of the plate, along X. Cannot be negative. |
200 mm (8 in) |
Height |
Overall height of the plate, along Y. Cannot be negative. |
200 mm (8 in) |
Hole D |
Diameter of each bolt hole. Every hole is the same size. Cannot be negative. If Hole D is 0 no holes are cut; a single point is placed at each hole centre instead. |
12.5 mm (0.5 in) |
Horiz. Pitch |
Centre-to-centre distance between bolt holes along X. Cannot be negative. |
100 mm (4 in) |
Vert. Pitch |
Centre-to-centre distance between bolt holes along Y. Cannot be negative. |
100 mm (4 in) |
Hole Offset X |
Moves the bolt hole pattern and the post circle along X from the centre of the plate. Positive moves right, negative moves left. The plate outline does not move. |
0 |
Hole Offset Y |
Moves the bolt hole pattern and the post circle along Y from the centre of the plate. Positive moves up, negative moves down. The plate outline does not move. |
0 |
Num. of Cols |
Number of bolt hole columns across the plate (along X). Whole number, minimum 1. |
2 |
Num. of Rows |
Number of bolt hole rows up the plate (along Y). Whole number, minimum 1. |
2 |
Post D |
Diameter of the post circle at the centre of the hole pattern. Cannot be negative. If Post D is 0 the circle is left out and a single point is placed at the post centre instead. |
50 mm (2 in) |
The dimensions drawn on the shape are Width, Height, Horiz. Pitch, Vert. Pitch, Hole D and Post D (both as diameters). The Post D dimension is always drawn at the centre of the plate, even when the hole offsets move the post circle.
Limits
The shape does not check that the holes and the post circle fit on the plate or clear each other. If the geometry cannot be built at all, the property page shows Warning: Cannot build shape from these parameters. Otherwise keep these conditions yourself:
•The hole pattern must fit inside the plate: (Num. of Cols - 1) x Horiz. Pitch + Hole D + 2 x |Hole Offset X| must be less than Width, and (Num. of Rows - 1) x Vert. Pitch + Hole D + 2 x |Hole Offset Y| must be less than Height.
•The post circle must clear the nearest bolt hole: Post D / 2 + Hole D / 2 must be less than the distance from the post centre to that hole centre. With the default 2 x 2 pattern that distance is half the diagonal of the pitch rectangle, √(Horiz. Pitch² + Vert. Pitch²) / 2. If Num. of Cols or Num. of Rows is odd, a hole lies on the post centre line and can be much closer to the post: Vert. Pitch / 2 away when Num. of Cols is odd and Num. of Rows is even, Horiz. Pitch / 2 away when Num. of Rows is odd and Num. of Cols is even, and at the post centre itself when both are odd.
•Post D + 2 x |Hole Offset X| must be less than Width, and Post D + 2 x |Hole Offset Y| less than Height, or the post circle crosses the plate edge.
If the post is welded on top of the plate and no circle is wanted for it, set Post D to 0. The shape then places only a point at the post centre.
Every 2D shape also has the Transform properties (Base X, Base Y, Rotation, Scale, Mirroring X) and the Polar Array properties, listed after the shape's own properties.