Do’s and don’t’s for view creation and dimensioning
you are telling a story about how your object is to be made, and you are
pointing out the various steps to the “builder”.
you must be able to convey the entire build of your object without words and
without causing the builder to ask you questions.
- VIEW CREATION
- Your first consideration needs to be
the presentation of appropriate views to show all detail in solid object
- To do this you will need not only the
traditional orthographic views but will need section and/or auxiliary
views to fully illustrate your model.
- To be meaningful all views must show
hidden lines, however you will rarely dimension to a hidden view. The
exception to this is section views which DO NOT have hidden lines shown. Detail
Views also do not show hidden lines with a few exceptions.
- Because Solid Modeling gives us a
free isometric view, use it to fully visualize the model. Generally you
do not dimension in this view BUT if you do be sure to use “TRUE”
dim is one that shows the true length of the object regardless of its
- FEATURE DIMENSIONING
- Each feature must be fully controlled
by your dimensions. There will be at least 3 dimensions associated with
each feature, generally reflecting the X, Y and Z locations/detail.
- Each dimension you place must be
- Indicate symmetry using Center Lines and
dimension off these Center Lines
- The Center Line Symbol; ; is added to non circular
symmetry lines. (Center Line Linetype)
- Object lines are usually dimensioned
in their true length, hence the use of auxiliary views.
are an exception to this rule and are generally dimensioned with an X,Y dim or X & Angle or Y & Angle. The hypotenuse is
never dimensioned. This is a special circumstance as a general rule of thumb is
that all objects are dimensioned in their true length.
- CIRCULAR FEATURES
- Add Center Points and Center Lines to
all circular features.
- If an object is circular you MUST
dimension to the Center Point.
- If you are dimensioning to circular
objects on a view it is preferable to use a leader dimension.
- You must NEVER dimension to the edge
of a hole. It is impossible to measure.
- If your have several holes on a
common centerline and the same size collect them using 1 dimension
statement followed by the note (X) to indicate quantity and be sure the
centerline is extended to capture all Center Points of the holes. Use X,
Y dimensions collectively as well.
- If you have made your hole features with the hole wizard you will be able to
use the hole call out for the dims. This gives you a note for all info
relating to the hole such as ID, Thread, C’Bore
or C”sink, depth and so on. (This is great incentive to use the
hole wizard to make all holes!)
- DIMENSION QUANTITY & QUALITY
- Avoid under dimensioning and over
dimensioning. Each dimension can be shown only once on the entire
dimensioning means that you are missing part of the information to create the
Dimensioning means that you have too many dimensions. This is a problem because
of a condition known as TOLERANCE STACK UP. This means that if you add up the
sum of all tolerances on each dimension the total is larger than the tolerance
allowed for the overall dimension. Thus you have created a Catch 22 situation
for the builder and more importantly for yourself as your can’t reject his work
as long as he falls within each tolerance.
- DIMENSION STYLE
- Dimensions are always layered with
the largest outermost and the smallest inner most to eliminate crossing
over of extension lines.
- The traditional gap between an object
line and the extension line is 1/16”. Make sure you adjust your
extensions lines to reflect that gap.
- Place dimensions in the view that
best shows the feature.
- Place dimensions for a feature as
close to each other as you can to make a complete statement about the
- Do not allow a visual conflict happen
with your dimensions and dimension lines
- No dimensions are to reside within
the object lines.
- Leader Lines are ALWAYS presented at
an angle. Never at angles of 0, 90 ,180 or 270
In your application turn off the option
that allows for automatic dimensioning. This forces you to think about the placement of each
it will save you time and agony over learning about and producing excellent