What makes CAD drawings unexpectedly increase in size?

Some users have complained about how their drawings increase in size and it’s getting harder to work on their drawings because the copy and paste are not available.

But what makes a CAD drawing unexpectedly increase in size?

1.Drawings are saved to lower versions

If you are using higher version of CAD, you would use graphics that are not supported by lower version of CAD such as tables, dynamic block, etc. All these data need to be converted in order to be normally displayed in lower version and then converted back when in higher version of CAD, which would definitely increase the file size. So we should save the drawing to the default version in CAD and convert it to lower version when necessary.

2. Redundant formats and blocks in CAD drawing

It’s normal to generate redundant data when using CAD just like using any other software, for example, we have defined layer, text style, dimension style without using them, but this won’t cause much increase in size. It is the overuse of blocks that will make the drawings larger and larger.

Some users like to use Copy and Paste as block, then explode them thinking that the blocks would be gone, but that’s not the case. When blocks are defined, even if all blocks are deleted or exploded, the definition of block would exist and could be inserted to drawings anytime. If you use I ( Insert) to check the block list, you may find hundreds of or even thousands of blocks are out there. If you purge those blocks, the file size would be times smaller.

3. Explode dense Hatch spacing

Some drawings have very dense hatch spacing, which may consist of tens of thousands of hatch lines. To display them requires generating more data, which will not cause the file increase, but exploding them is another thing since exploding those hatches and then save the file would record hundreds of thousands lines’ data, directly increasing the file size.

4. Large number of orphaned DGN line styles

This kind of data is like virus spreading, the file size gets bigger and bigger every time we copy and paste. We may get this kind of data by Copy and Paste instead of directly importing from a DGN drawing. The PU (Purge) command is designed to deal with such data.