# TOLERANCE Dialog box
[GstarCAD 2020](Help%20System/GSTARCAD/2020/Index.md) → [Commands](Help%20System/GSTARCAD/2020/Commands/(Commands).md) → [03 Dialog Boxes](Help%20System/GSTARCAD/2020/Commands/03%20Dialog%20Boxes/(Dialog%20Boxes).md)
The TOLERANCE dialog box is used to specify the symbols and values for a feature control frame.
Function Description:
After selecting geometry features symbols, the Geometric Dialog box closes and prompts to specify the location to place the feature control frame.
Relative Glossary:
**Symbol:**
Select a geometric characteristic symbol from "Symbol" dialog box.
**Tolerance 1:**
Create the first tolerance value in the feature control frame. The tolerance value means the amount by which the geometric features can deviate from a perfect shape. Users can insert a diameter symbol.
> **The first box:**
> Click the first box to insert a symbol. For example, insert a diameter symbol.
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> **The second box:**
> Create a tolerance value. Input a tolerance value to the second box.
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> **The third box:**
> Display the "Material Condition" box, from which users could select a modifying?symbol. Those symbols act as modifiers to the geometric characteristic and the tolerance value of features that can vary in size.
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**Tolerance 2:**
Create the second tolerance value in the feature control box. Specify the second tolerance value in the same way as the first one.
**Datum 1:**
Create the primary datum reference value. The datum reference is composed by a value and a modifying symobl. In theory, the datum is an accurate geometric reference, which is a tolerance zone used to create features.
> **The first frame:**
> Create a datum reference value.
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> **The second frame:**
> Display the "Material Condition" box, from which users could select a modifying?symbol. These symbols act as modifiers to the datum reference.
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**Datum 2:**
Create the secondary datum reference in the feature control box, which is in the same way as the primary datum reference.
**Datum 3:**
Create the tertiary datum reference in the feature control box, which is in the same way as the primary datum reference.
**Height:**
Create a projected tolerance zone value in the feature control frame. A projected tolerance zone controls the height variation of the extended portion in the fixed perpendicular part, as well the location tolerance controls the tolerance accurancy.
**Projected Tolerance Zone:**
Insert a projected tolerance zone symbol after the projected tolerance zone value.
**Datum Identifier:**
Create a datum-identifying symbol consisting of a reference letter. A datum is a theoretically exact geometric reference from which you can establish the location and tolerance zones of other features. A point, line, plane, cylinder, or other geometry can serve as a datum.
## Other versions with matching text
[GstarCAD 2016](../../../2016/Commands/03%20Dialog%20Boxes/TOLERANCE%20Dialog%20box--fe5dfae4af98.md) · [GstarCAD 2017](../../../2017/Commands/03%20Dialog%20Boxes/TOLERANCE%20Dialog%20box--fe5dfae4af98.md) · [GstarCAD 2018](Help%20System/GSTARCAD/2018/Commands/03%20Dialog%20Boxes/TOLERANCE%20Dialog%20box--fe5dfae4af98.md) · [GstarCAD 2019](../../../2019/Commands/03%20Dialog%20Boxes/TOLERANCE%20Dialog%20box--fe5dfae4af98.md) · [GstarCAD 2021](../../../2021/Commands/03%20Dialog%20Boxes/TOLERANCE%20Dialog%20box--fe5dfae4af98.md)