Blocks

The concept of blocks originated in AutoCAD. Blocks allow you to combine one or more objects into a single reusable object. As you work in AutoCAD or AutoCAD Architecture, you can insert blocks repeatedly in the drawing at various locations, orientations, and scales. If you change a block, the changes propagate automatically to all instances of that block throughout the drawing.

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 or AutoCAD Architecture 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.

NoteA change to the drawing in AutoCAD or AutoCAD Architecture is reflected in 3ds Max when you reload the linked model. Changes made in 3ds Max do not propagate back to AutoCAD or AutoCAD Architecture.

Block and Modifying Linked Geometry

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.

NoteAny 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.

Limitations of Blocks

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 cannot change the color of linked blocks or their components. Their color is set by layer when they're built in AutoCAD or AutoCAD Architecture.
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.
You cannot collapse the modifier stack of an actively linked object.
Layer assignments of linked geometry cannot be changed in 3ds Max if an object is actively linked. Layers can be reassigned if the model is bound.
Cloning a block or block component is not possible if it is actively linked. You cannot select a block and use Shift+drag to duplicate it. This is also true for tools like Array, Mirror, and the Spacing Tool. Once a block or block component is bound, you can clone it.

Blocks and Materials

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 AutoCAD Architecture.

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.

NoteWhen 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 Maps topic.

Multi-View Blocks (MVBlocks)

3ds Max accommodates both AutoCAD blocks and AutoCAD Architecture 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 AutoCAD Architecture multi-view blocks is expressed differently than AutoCAD blocks in 3ds Max. 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 AutoCAD Architecture 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 AutoCAD Architecture 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 do 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.

Dynamic Blocks

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.

Property	Behavior
Modifiers	Modifiers applied to one component are applied to the same component in other instances, but only when those instances have the same grip property values.
Materials	When material propagation is turned on, materials are applied to all block instances. When turned off, materials are applied only to the current selection set. NoteIf you use the Entity, Blocks as Node Hierarchy Derive By setting for drawings containing dynamic blocks, materials may propagate to some block instances and not to others.
Node Properties	Changes to node properties are not propagated to block instances.
Transforms (on components)	Transforms, like move, rotate and scale, of one component will affect that same component in other block instance only when those instances have the same grip property values.

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.

Modifier behavior of Dynamic Blocks during a File Link Reload

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.

Blocks and Interactive Selection and Navigation

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.

With complex drawings, 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 From Scene dialog.
Another selection method uses the Layer or Color setting you made for your block when you created it in AutoCAD Architecture. 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 you’ve selected a block or set of block instances, you can isolate them from the remainder of the model to work on them more efficiently.

To select a block by color:

Choose Edit menu Select By Color.
Select a block in the scene.
All blocks that share that color are selected.

To select blocks by name:

Choose Edit menu Select By Name, or press the H key to open the Select From Scene dialog.
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.
Click Select.
All blocks that share the specified name are selected.

To select blocks by layer:

Choose Edit menu Select By Layer.
Select a block in the scene.
All the blocks sharing that layer are selected.

To isolate selected objects:

Using one of the previous selection methods, select some blocks.
Choose Tools menu Isolate Selection.
This hides all objects except for the selected blocks. A dialog is opens, indicating that isolation mode is active.