Image “Carving a Chinese Printing Block” by Jonathan Kos-Read – Flickr
To create a block you start with creating the geometry. There isn’t really much of a limitation in that you can create any type of objects you want, except remember that the key is consistency. Blocks within AutoCAD serve many purposes but mostly to provide a convenient method to reuse content while maintaining consistency from drawing to drawing. Try to remember consistency as you build your blocks so that you get a familiar look and feel to everything you create. What about the layers the objects are on? Good question, and conveniently enough I’ve covered this before in our Deep Dive Series on Blocks, which you can read here. The key to working with blocks and layers is understanding the importance of Layer 0. If the geometry contained within the block resides on layer 0 this geometry will take on the properties of the layer the block is placed on. Therefore if the block is on a red layer with a hidden line type all objects within the block on layer 0 will appear red with a hidden line type.
To create a new block definition you use the Make Block feature. Make Block can be initiated by typing B (and pressing Enter) with the keyboard or by selecting Create Block from the Insert Tab > Block Definition Panel.
- Specify the Name of the Block. The block name must be unique within the drawing. The drop-down lists all block definitions that exist in the current drawing. Use this to double-check your block name is unique or select an existing block name to overwrite (redefine) an existing block.
- Set the Base Point. The base point becomes the insertion point, as in the point on the block your cursor will be at when you insert the block into your drawing. The base point can be defined by keying in the coordinates, using the pick button to select a point in the drawing, or by enabling the Specifying on Screen option. Specifying on Screen means that you will pick the point after you click OK.
- Select the Objects. No point in having a block if it doesn’t contain any geometry. Click the pick button to select the objects in the drawing window or enable Specifying on Screen to select the objects after you click OK.
- Decide what to do with the original objects. The objects you select to create the block can become a block (Convert to block), can be deleted (Delete) or do not need to become a block themselves. and remain as is (Retain)
- Should the block be Annotative? An annotative block is one that will adjust in size as the drawings annotation scale is adjusted
- Should the block scale uniformly? When enabled the block must scale in the Y-direction the same amount as being scaled in the X
- Should we allow the block to be exploded? when enabled you will NOT be able to explode the block instance in the drawing.
- Select the Block Unit Type. Blocks can scale according to the drawing unit. For example if the block was set to inches and the drawing to millimeters when inserted it would be 25.4 times larger than originally defined Why? There are 25.4 mm in an inch.
- Add a Hyperlink (optional). A hyperlink is a link to something, whether it be a web page, an email, another document, or to a view in the drawing.
- Be Descriptive (optional). Not everyone will understand what your block is for from the name alone, by adding a description you make it easier for others to know what the block is for before they insert it.
- Open it in the Block Editor (optional). If you intention is to make a Dynamic Block (discussed later in this series) then you’ll want to open the new block in the Block Editor to add dynamic features.
When satisfied with the inputs click OK to build your block.
So you’ve created your block… now what? Insert your block into your drawing to test it out. The insert block feature can be accessed from the Insert tab of the ribbon or by typing I with the keyboard.
- Select the Block you want to Insert
- Optionally Browse for a drawing and insert the entire drawing in as a block
- Set the insert point either by keying in the coordinates or enabling Specify on-screen to pick the point after clicking OK
- Specify the Scale either by keying in the scale factors or by enabling Specify on-screen to set the scale after clicking OK. With the example above the Y & Z fields are disabled as this block was created with the Uniformly Scale option enabled. With this option disabled the X, Y, and Z scale factors can all be set independently.
- Specify the Rotation either by entering the rotation angle or by enabling Specify on-screen to pick the rotation after clicking OK
- Block Unit reference lists the Unit of the block and the factor that will be applied with the block is inserted. The factor is based on the Block Unit compared to the units of the drawing
- Optionally Explode the block during insertion. By exploding a block the objects are returned to original form, ungroup, and not contained within a block
After the block is inserted you can make adjustments to it very similarly to other 2D objects. Blocks can be moved, copied, scaled, rotated, mirrored, and adjusted with grips. Blocks can be exploded to remove the block and leave the blocks geometry. Copying a block can be faster and more efficient than inserting another instance. http://youtu.be/tBbamPpJJcI