AutoCAD Architecture: Creating Multi-view Blocks using
the Hidden Line Projection Tool
When users are working in complex and busy drawings,
multi-view blocks (MV Blocks) can be created and
utilized to reduce the processing time required to
regenerate various views.
For example, if you are working on a 1st floor office layout
in a large commercial office, it would be better and less
taxing on your hardware to use multi-view blocks rather than
3 dimensional models solely for placing instances of your
objects (desks, chairs, cubicles, etc) in a furniture
layout. This can be achieved by creating multiple view
blocks of the object with varying degrees of detail and
assigning them to display representations and view
directions.
Hidden Line Projections create a 2D graphic from a
3D view of one or more objects in your drawing. The 2D
graphic that you create is a flattened representation of the
objects in the current 3D view, with hidden background
lines. Use the Hidden Line Projection command to create
quick 2D elevations and sections.
When you create hidden line projections, the 3D objects
that you select are copied and collected into an unnamed
(also called anonymous) 2D block. The unnamed block can be
placed in your drawing in the current 3D view, or placed
parallel to the XY plane to be viewed in plan view. You can
edit or explode the inserted block and redefine the block
for other uses.
The following example will show you how to create a
multi-view block using the Hidden Line Projection tool once
you have a 3 dimensional model of the object. For this
example, we will start with a 3D model of a desk.
Figure 1
Step 1
Figure 1 shows a 3d model of a desk. There are 3 main
principles we want to pay close attention to when creating
multi-view blocks. They are:
-
Make sure you are in the World UCS when creating view
blocks
-
Follow a logical naming convention for your view blocks
-
Insertion points MUST be thought out and planned
You will now change the UCS to World, then define the
model block as Desk-30x60-Model, choose all geometry
as well as the points with the select objects button, and
select the blue point (shown) as the insertion point for the
block.
(Note Adding points on the defpoints layer allows for
multiple insertion points for multi-view blocks when
inserting them into drawings. You can cycle between the
insertion points by hitting the CTRL key.)
Step 2
Change to the Front view and change the UCS to World and
start the Hidden Line Project tool (found under the Document
pull down menu) shown in Figure 2. Then, select the 3D model
of the desk, press ENTER and then specify an insertion point
for the unnamed block. You will then be prompted to insert
the block in plan view, yes or no, choose No to insert the
block in the current view.
Once you have created your view blocks using the Hidden Line
Project tool, you will need to explode the unnamed blocks
and redefine them following your naming convention and by
specifying proper insertion points for each.
Figure 2
Step 3
Follow step 2 for each additional view, Top, Right, Left and
Back. Once you have created each view block, position them
in alignment with the 3D model block so the insertion points
will align properly when changing views after a Multi-view
block has been inserted.
You must be sure that you are in the World UCS before
redefining the unnamed blocks. The illustration in Figure 3
shows each view block in alignment with the 3D model block
and the blue grips depict the proper placement for the
insertion point of each.
Figure 3
Step 4
Once you have created all required view blocks with proper
naming and insertion points, you will then create a new
Multi-view Block style definition.
Open the Style Manager, expand the Multi-Purpose Objects and
Multi-view Blocks, Right Click on Multi-view Blocks and
choose New from the menu. Name the MVBlock Style Desk
30x60 (shown in Figure 4).
Figure 4
In the view window, the View Blocks Tab on the right will
be displayed. You now add the view blocks you want
associated with the various display representations and view
directions by selecting each representation and clicking on
the Add button. Figures 5, 6, 7, 8, 9 and 10 show examples
of different vies blocks assigned to particular view
directions for the Plan Display Representation. Click Apply
and Ok to exit the Style Manager.
Figure 5
Figure 6
Figure 7
Figure 8 (Other represents isometric views and all other
non preset default views)
Figure 9
Figure 10
Once you have created your MVBlock Style, you can now
insert instances into your drawing using the Insert pull
down and choosing Multi-view Block. MVBlocks help to
maximize system performance by reducing the regeneration
time required when working with 3 Dimensional objects in
complex drawings. The Hidden Line Project tool aids you in
quickly generating the required view blocks that are used to
define the MVBlock style.
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