The concept of blocks originated in AutoCAD. Blocks allow you to combine one or more objects into a single reusable object. Blocks can be repeatedly inserted in the drawing at various locations, orientations, and scales. Changes made to a block propagate automatically to all instances of that block throughout the drawing. Like all drawing construction, inserting or deleting blocks occurs while you work in AutoCAD or Architectural Desktop.
You then link the DWG file to 3ds Max, where your goal is to beautify the scene in preparation for rendering. Some of those preparations include such procedures as selecting a block instance so you can apply or adjust a material, applying texture mapping coordinates, unifying or flipping normals, and setting rendering properties. These procedures affect all other block instances in the scene.
The structure of nested blocks, blocks that are made from multiple sub-blocks, is maintained when you link an AutoCAD drawing to 3ds Max. For example, if the block Desk1 is made using several blocks, Desk, Chair and Return, you will be able to select any of Desk1's sub-blocks to alter their rendering properties or materials. You can only access rendering properties for block components that appear as Linked Geometry on the Modifier panel. Blocks or sub-blocks, that appear as VIZBlocks in the Modify panel, do not have rendering properties because they are not renderable.
Note: A change to the drawing in AutoCAD is reflected in 3ds Max when you reload the linked model. Changes made in 3ds Max do not propagate back to AutoCAD.
Linked objects show up as linked geometry objects in the modifier stack. These objects don't allow access to sub-object levels where minor editing can occur at Vertex or Face levels. You must first add an Edit Mesh modifier to the object in order to access sub-object levels where you can perform operations like welding vertices or deleting faces. If you add a modifier to a block, the modifier is applied to all instances of that block. Likewise, any sub-object level editing to the originally selected block propagates to all other instances.
Note: Any modifiers you apply to a block or block component in 3ds Max are preserved if you reload the file with the File Link Manager.
If you move, rotate, or scale blocks or block components in 3ds Max, their new transform is preserved even if the linked model is reloaded from AutoCAD. Transforms applied to linked geometry in 3ds Max are relative to the transforms applied to the same objects in AutoCAD. Further, the transform propagates to all instances of that block or component. For example, if you move the Chair component of Desk1, the Chair component of all Desk1s in the scene will be moved. If the transform is undesirable, you can use the Reset Transform button on the Modify panel to put the block or component back to its original position.
When a modifier is applied to a block or block component, it propagates throughout all instances of the block or block component in the scene.
Blocks have some limitations when you link a drawing to 3ds Max.
You cannot change the structure of actively linked blocks or their components in 3ds Max. In order to delete a block or component, you will have to bind the file, breaking the link.
You can only access rendering properties for block components that appear as Linked Geometry on the Modifier panel. Blocks or sub-blocks, that appear as VIZBlocks in the Modify panel, do not have rendering properties because they are not renderable.
When assigning a material in 3ds Max to an instance of a block or block component, all the instances of that block or component are assigned the same material automatically. This is called automatic material propagation. This feature helps align 3ds Max behavior with that of Architectural Desktop.
If you find that a material you've assigned to a block or block component is not what you wanted, you can undo the material assignment by choosing Edit menu > Undo or pressing Ctrl+Z. If you undo a material assignment, the undo will propagate to all instances of the objects to which you assigned the material.
Note: When assigning a material to a block or block component, you are not prompted to accept or cancel the material propagation. You can only control propagation of materials by toggling Propagate Materials To Instances.
For more information about working with materials and assigning materials to blocks in 3ds Max, see the Material Editor, Materials, and Mapping topic.
3ds Max accommodates both AutoCAD blocks and Autodesk Architectural Desktop multi-view blocks through the file linking functionality, and for the most part the two block types behave similarly in 3ds Max with some exceptions.
The structure of Architectural Desktop multi-view blocks is expressed differently in 3ds Max, when compared to AutoCAD blocks. Rather than peer into the internal structures of multi-view blocks as is done with AutoCAD blocks, 3ds Max relies on the multi-view block's own ability to draw its own 3D view, much as it does in the Architectural Desktop Object Viewer. Because of this, you will notice that multi-view blocks never exhibit nesting in their object structure when they are file linked into 3ds Max.
Behavior of instanced Architectural Desktop multi-view objects is different from that of AutoCAD blocks as well. Multiple instances of multi-view blocks require more memory in 3ds Max than multiple instances of AutoCAD blocks. But multiple instances of multi-view blocks are better behaved when being cut by live section objects than their AutoCAD counterparts.
The File Link Manager handles dynamic blocks the same way as other blocks found in a DWG file. When linked to a scene, the naming for the incoming dynamic block instances are based on the original dynamic block definition in the form of Block: block_name where block_name is the actual name of the dynamic block definition.
Dynamic block instances, even those that have been grip-edited, display certain types of instance behavior such as material propagation, if the setting is activated from the Material Editor Options menu. Below is a table showing instance behavior of dynamic blocks.
Keep in mind that elements of a dynamic block can be turned on and off by certain grip-edit operations depending on the way the dynamic block is defined. When one instance has a component and another doesn't, instance behaviors cannot occur between them because they are treated as instances of one another.
There is no change in modifier behavior for dynamic blocks that have not been grip-edited between one Reload and the next. All properties (materials, modifiers, node properties) are preserved. Dynamic blocks that have been grip-edited preserve their node name, node properties, scene-applied transform, and materials, but may lose applied modifiers and/or may inherit modifiers. This table shows the behavior of modifiers during a File Link Reload before and after dynamic block editing.
| The Block Insert ... | ||
|---|---|---|
| ... has unique parameter values before it was edited. | ... has unique parameter values after it was edited. | ... shows this modifier behavior upon Reload. |
| Yes | Yes | Modifiers are preserved. |
| Yes | No | Applied modifiers may be lost, and it may inherit modifiers from the instance(s) it now matches. |
| No | Yes | Applied modifiers are lost. |
| No | No | Applied modifiers may be lost, and it may inherit modifiers from the instance(s) it now matches. |
Once blocks and block components are linked to 3ds Max, you can begin adjusting their materials and properties. In a drawing for a small apartment, blocks are pretty easy to locate because the drawing is not very congested. You can simply select a block or one of its components in the viewport and alter it.
When drawings get very complex, finding the block or block instance you want can pose a problem. For example, a common block you might add to a drawing is a table. If you're designing a corporate headquarters that makes use of several different types of tables, finding the one you want to change becomes more difficult. There are several ways for you to find and select a block more precisely in 3ds Max.
One way is by means of the block's name. When you link a drawing to 3ds Max, file linking creates a name such as Block: ConferenceTable. The first part of the name identifies the object's type, Block. The second part of the name indicates the block name, ConferenceTable. With this sort of naming breakdown, you can easily find a block using the Select Objects dialog.
Another selection method uses the Layer or Color setting you made for your block when you created it in Architectural Desktop. Because layer and color data is also linked to 3ds Max, you can select entire groupings of blocks using Select By Color or Select By Layer.
Finally, you can select blocks by the type of material that's applied to them. Take care when selecting blocks this way because the material assigned to the block may also be assigned to other objects in the scene.
Once a block or set of block instances is selected, you can isolate them from the remainder of the model to work on them more efficiently.
To select blocks by name:
Choose Edit menu > Select By > Name, or press the H key to open the Select Objects dialog.
Alternately, you could use the Selection Floater, accessed from the Tools menu. While similar to the Select Objects dialog, the Selection Floater is modeless and can remain on-screen while you're working.
While holding down the Ctrl key, select blocks with common names.
You can also enter the block name in the name field at the top of the dialog.