Assembly blocks with Autocad. Component layers and Pspace.

Autocad Task 45 Return to Home Page

Task Fourty Five.

Perform a zoom > all >. The three assembled parts in the top left drawing sheet need to be turned into a block. Proceed as follows.

Ensure no mviews are active and zoom to the top left assembly drawing sheet. Activate the pictorial view. Remain in the Wcs and MAKE THE ASSY01 LAYER CURRENT. Initiate the block command (as shown in task 43) and call the block ASSY01. Pick all three components at the "select objects" prompt and create the block at 0,0,0.

Reset Pspace again and perform a Zoom - All.

The display should show an assembly in one set of Mviews and one of the components in each of the other sets of Mviews - again like Fig Tsk 41. When this is the case, the model is complete and the VPL layer can be turned off. However, some views may remain blank when zoomed. Read on.

If one or more of the sets of Mviews is empty check the layer that each block resides on. It is VITAL that blocks reside on the layer of the same name and that each component block consists of ONE component. Only assembly blocks can have more than one component. Block CMPT01 should be onlayer CMPT01 etc. culminating with the ASSY01 block on layer ASSY01. If the block and layer relationships don't appear to correspond to each other, use the Explode command and then re-establish the blocks with block CMPT01 on layer CMPT01, block CMPT02 on layer CMPT02 etc. When blocks and layers are accurately established, the display shows an assembly in one set of Mviews and one of the components in each of the other sets of Mviews. If components still don't display, explode all the blocks and, paying particular attention to layer and block names, continue the tutorial again from Task 41. The next section re-iterates how this block / layer structure works.

Understanding blocks and component visibility.

The three groups of entities discussed after task 41 in the section headed "Layer Management For Complex Designs" are now complete. In brief, the model entities (lines, circles etc.) are on layers 01, 02, and 03. These in turn were blocked on layers CMPT01, CMPT02, and CMPT03. The final block was the ASSY01 block consisting of the three CMPT blocks. Block names are the same as layer names to ease identification.

Component visibility needs to be managed in specific Mviews so Vplayer HAS to be used to freeze / thaw layers. Vplayer is a command that allows layer manipulation to be applied to specific Mviews. If the Layer command were used instead of Vplayer, components would be affected globally in all Mviews, and in both of the model and drawing environments. The consequence would be that ALL views would reflect the outcome if the Layer command was used.

Consider a layering situation within one Mview as follows:-

If the ASSY01 block were frozen using Vplayer, nothing would be visible. If one CMPT layer were frozen only the component on that layer would vanish. The correct approach is to have everything frozen except the entity layers, ASSY layer and CMPT layer that are needed.

When too little attention is paid to block and layer management, confusion can easily arise regarding what's displayed. Imagine having two components on one CMPT layer. If that layer were to be displayed, both components would always be visible. The reverse situation can happen if entity layers are frozen. For example, a large project may have three of the many components modelled on layer 04. If layer 04 is then frozen, all three components will vanish, regardless of being on separate CMPT layers.

Take some time to fully understand the layer structuring shown in these tutorials. It is the key to working efficiently with several 3D items in one model.

Save your work and move on to Tutorial 4.

Tutorial 4

Tutorial 4 deals with detailing philosophy, dimension scaling and the associated commands to ensure dimensions and view scales relate to each other correctly. Up-issuing is also dealt with.

Now move to the next page to continue with Task 46.

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