Building Blocks

Creating a library of blocks is something you should be conscious of with every drawing you work on. Whenever you draw a part or component, you need to ask yourself one simple question — "Am I ever likely to need one of these again?" If the answer is yes, you should follow the steps below to add this component to your part library. If the answer is no, maybe you should ask the question a second time. In most cases it's much easier to bring in a standard part, explode and modify it, than it is to redraw a part from scratch.

With this in mind you can decide whether you want your blocks to have hardcoded colours or whether you like the flexible approach of defining block colour at insertion time.

Creating a block using the BLOCK command in IntelliCAD

One aspect of block creation that is disconcerting for new users is that objects used to create a block disappear from the screen when the block command operates successfully. You can get these objects back with the OOPS command, which brings back erased objects. The block command stores the block definition permanently within the drawing, even if the block isn't actually inserted and visible. Unwanted block definitions can be removed from the drawing with the PURGE command. Blocks are placed on the drawing with the INSERT or DDINSERT commands and can be scaled and rotated when inserted.

Blocks can be inserted into other drawings using three main methods. Firstly, you can copy a block to the Windows Clipboard and Paste it into another drawing. IntelliCAD allows you to open several drawings within a single session and tile drawing windows to provide access to areas within different files. You can use this feature to open a drawing containing several blocks, which can be cut and paste as required.

The second method also involves cut and paste but provides access to block names using the Drawing Explorer. From the Tools menu select Drawing Explorer or type EXPBLOCKS at the command prompt. The Drawing Explorer allows you to navigate various drawing files and the right mouse button provides access to cut and paste options.

Using the WBLOCK command in IntelliCAD to create a part library on disk.

The WBLOCK method is more time consuming but ultimately of more benefit if a number of people access the CAD system. Creating a unique central directory location for the company part library is a good approach and allows all operators to create and access blocks within a logical structure.

Using blocks generally lowers the file size of your drawings. Let's take the example of a 100Kb block that is inserted 20 times within the drawing. For a single block insertion this approach is actually less efficient because the drawing stores the block definition at 100Kb and then some additional data for the insertion point, scale factor and rotation angle of the single block insertion. With 20 instances of the same block, however, drawing size won't grow significantly. Compare this with copying the original geometry 20 times, which adds 2Mb to the file size.

Blocks can be taken back to their original geometry components with the EXPLODE command but watch out for swollen file sizes with unexploded blocks that aren't purged. Take the example of a 1Mb drawing file where I insert a 1Mb block, giving me a 2Mb file. If I explode the block but don't carry out a purge, my drawing will grow to 3Mb because it must store the original 1Mb block definition, as well as the 1Mb of exploded data.