The SEDRIS Data Representation Model
APPENDIX A - Classes Translation Control Link |
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An instance of this DRM class is a specialized <Control Link> instance used to provide the connection between an ordered aggregation of <Expression> instances and the target fields of a <Translation> instance.
Consider a <Geometry Model> instance representing a building,
containing a <Geometry Model Instance> instance representing
a lift cage (elevator car), where both <Model> instances are
specified in a 3D LSR SRF, and the lift cage is intended to be a moving
part of the building model. The <LSR Transformation> instance
used to instance the lift cage into the building specifies a
<Translation> component with a
<Translation Control Link> instance
as depicted in
This <Translation Control Link> instance specifies:
A <Literal> component, defining the lower limit (the bottom of the lift shaft) of the translation, in this case, 0.0 metres.
A <Literal> component, defining the upper limit (the top of the lift shaft) of the translation, in this case, 500.0 metres.
A <Variable> component, the actual translation of the lift cage along the lift shaft's W axis at any given moment.
The <Variable> instance's meaning = {SE_ELEM_CODE_TYP_VARIABLE, {SE_VAR_CODE_TRANSLATION_AMOUNT}}
The <Variable> instance's value_unit = EUC_METRE and its value_scale = ESC_UNI, because <Translation> instances define their fields in metres.
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SE_String | description; | (notes) |
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SE_Integer_Positive | expr_index; | (notes) |
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SE_Integer_Unsigned | lower_expr_index; | (notes) |
SE_Integer_Unsigned | upper_expr_index; | (notes) |
The description field specifies a text description of the purpose of the <Control Link> instance.
For a given <Translation Control Link> instance C, expr_index serves as a one-based index into the ordered <Expression> components of C such that the specific <Expression> instance selected specifies the value of the translation_amount field of each <Translation> instance controlled by C.
For a given <Translation Control Link> instance C, if lower_expr_index > 0, it serves as a one-based index into the ordered <Expression> components of C such that the specific <Expression> instance selected specifies the lower limit for the translation_amount of each <Translation> instance controlled by C. If lower_expr_index = 0, it indicates that no such lower limit is being specified.
For a given <Translation Control Link> instance C, if upper_expr_index > 0, it serves as a one-based index into the ordered <Expression> components of C such that the specific <Expression> instance selected specifies the upper limit for the translation_amount of each <Translation> instance controlled by C. If upper_expr_index = 0, it indicates that no such upper limit is being specified.
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