Scale by factors and shrinkage allowance

The Scale tool (SS) scales evenly or drags a grip to stretch one or two directions. Scale by factors… (Tools menu, or the Modify group) is the typed form: a number for each of the three axes.

1. Select edges, faces, groups or components.
2. Open Scale by factors…. Type a factor for red, green and blue. A factor can be 1.015, 101.5% or +1.5% (and -2% for smaller). Same on all three axes copies the first to the other two.
3. Choose what stays put: the middle of the selection, its lowest corner, the middle of its bottom, or the origin.
4. The line under the fields shows the size now and after. Scale does it in one undo step.

The axes are those of the group you have open (the model's, at the top level). A group or component that is turned comes out sheared if its factors differ; scale the group that holds it instead. The contents of a component are not touched, so its other copies stay as they are.

Shrinkage allowance

A cast part shrinks as it cools, so its pattern is made bigger. Under Shrinkage allowance type the percent for each axis (your foundry or pattern maker gives it for your metal; 1.5 % below is only an example) and press Use as the factors.

• The percent itself makes the factor 1 plus the percent: 1.5 % gives 1.015, what a shrink rule marks.
• Exactly enough makes the factor 1 divided by one minus the percent: 1.5 % gives 1.0152, so the casting comes out at the part's size after it shrinks that much.

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