# WeightCapacity in IfcTransportElement is a single value

**URL:** <https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669>\
**Category:** Developers\
**Created:** [May 5, 2020, 5:41pm UTC](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669 "2020-05-05T17:41:24Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![KavehAll](https://avatars.discourse-cdn.com/v4/letter/k/a4c791/32.png) [@KavehAll](https://forums.buildingsmart.org/u/KavehAll)\
**Post date:** [May 5, 2020, 5:41pm UTC](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669/1 "2020-05-05T17:41:24Z")

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[IfcTransportElement](https://standards.buildingsmart.org/IFC/RELEASE/IFC4_1/FINAL/HTML/schema/ifcproductextension/lexical/ifctransportelement.htm) is to be used to model cranes. It has a property set called

` Pset_TransportElementCommon` which has a property called `CapacityWeight` to set the lift capacity of the crane. The issue is that manufacturers provide a table of (Weight-radius)s for the crane not a single value.  
A crane has different lift capacities at different position of its jib .  
I am not sure if this is by design, but It would be nice if this can be addressed.  
Till then, I assume , one has to define a custom property to address this(?)  
Cheers,  
Kaveh

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**Author:** ![Moult](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/moult/32/196_2.png) [@Moult](https://forums.buildingsmart.org/u/Moult)\
**Post date:** [May 5, 2020, 9:39pm UTC](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669/2 "2020-05-05T21:39:14Z")

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Correct.

It would be good to fix this. Perhaps a select can be used.

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**Author:** ![DanPeel](https://avatars.discourse-cdn.com/v4/letter/d/ecccb3/32.png) [@DanPeel](https://forums.buildingsmart.org/u/DanPeel)\
**Post date:** [May 13, 2020, 7:09am UTC](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669/3 "2020-05-13T07:09:16Z")

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When crane manufacturers sell cranes they classify them according to their maximum capacity - ie their capacity at minimum lift radius. Cranes do have different performance curves as the radius increases but as a starting point you could just specify the maximum capacity in CapacityWeight - this woudl give 90% of people all the information that they need. If necessary you could use the custom property approach to specify a particular capacity at a particular radius.

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**Author:** ![Moult](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/moult/32/196_2.png) [@Moult](https://forums.buildingsmart.org/u/Moult)\
**Post date:** [May 13, 2020, 10:39pm UTC](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669/4 "2020-05-13T22:39:56Z")

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I propose, then, for `CapacityWeight` to change to `MaximumCapacityWeight` to make this convention more obvious, and then introducing a new property, perhaps called `CapacityWeights` or `CapacityWeightTable` for the various lift capacities.