You can also create and save your own hatching already at the correct metric scale using the F7 Manage (Hatch Pattern Manager).
Mark is correct, and that should work reasonably well in this case, as the brick size that you asked about is not dis-similar in proportions to the 'standard' brick that is represented in the supplied brick hatch patterns.
But the proportions are not identical, so if you really want to modify the existing hatch patterns you can do so with a text editor. The hatches are defined in .dhp files in the Support Files/hatch folder.
There is an old Cheap Tricks article about defining hatch patterns that may be of interest
. The article refers to an obsolete config file, but I believe the discussion of the actual line segment definitions is still applicable.
As an example, the line segment definitions in the supplied Brick.DHP file are as follows:
Code: Select all
001=0, 0, 0, 0, 0, 0, 2.666667
002=0, 0, 90, 0, 0, 2.666667, 4, 2.666667, -2.666667
There is only 1 non-zero parameter in line 001, and that is the 7th parameter which defines the y spacing. So this line defines a solid horizontal line that repeated vertically every 2.666667 units.
Line 002 is a little more complex:
- the 3rd parameter (90) refers to the angle of the line (thus it defines vertical lines).
- the 6th parameter defines the offset for each repeat of the line. This is the offset along the direction of the line, so as this line is vertical it is offset 2.666667 units along the y-axis with each repeat.
- the 7th parameter (4) defines the repeat spacing (since our line is vertical, this the the x spacing between line repeats).
- the subsequent parameters define pen up/down segments of the line. A negative number means pen up for that distance, a positive number means pen down.
This hatch pattern therefore defines bricks that are of the proportion 8 units long to 2.666667 units high (8 units long because the vertical lines offset by 2.666667 units with each repeat, so although they are repeated every 4 units the pen-up segment will be in each course of brickwork for every other line). This proportion ( 8 / 2.666667) equals approx 3 which is the same as the standard brick face proportion (230mm / 76mm is also very close to 3).
If you wanted to alter the proportions of the bricks you could do so by changing the numbers in the hatch file segments definition. Increasing all the '2.666667' numbers (or decreasing the '4') would result in a wider brick face, reducing the '2.66667' values (or increasing the '4') would result in a longer brick face.
Ignoring the 10mm joint for this example, you want a proportion of 215/65, or about 3.3. You could change all the '2.666667' numbers to '2.424242' to achieve the correct proportion, but I think it is more understandable to use the actual numbers. You could change all the '2.666667' ot '65' and change the '4' to '107.5' (i.e. 215/2) ... this would give the correct proportion, but would need to be appropriately scaled as datacad uses units of 1/32" but you want mm. Converting the metric distances to 1/32" units would produce the following hatch definition:
Code: Select all
001=0, 0, 0, 0, 0, 0, 78.11023622047244
002=0, 0, 90, 0, 0, 78.11023622047244, 135.4330708661417, 78.11023622047244, -78.11023622047244
Hope the above is helpful. I've attached a file with the above definition. Modifying other relatively simple existing hatches should not be too difficult using a text editor.