https://community.graphisoft.com/t5/Collaboration-with-other/Difference-between-Base-Quantities-and-ArchiCadQuantities/m-p/258824#M33841 Hi,<BR /> <BR /> I am not sure what the IFC value measures (I suppose the actual area of the 3D body on one side). Take the 3D model, start measuring it, and see which measurement might match the IFC value.<BR /> <BR /> For the ARCHICAD value though, <A href="https://helpcenter.graphisoft.com/?p=76908" target="_blank">here's a complete list of all the wall area parameters</A> you can list, with pictures. The General Surface Area parameter should measure the area of 'reference line'*'height' in case of walls.<BR /> <BR /> Regards, Sat, 10 Nov 2018 10:28:47 GMT Daniel Kovacs 2018-11-10T10:28:47Z https://community.graphisoft.com/t5/Collaboration-with-other/Difference-between-Base-Quantities-and-ArchiCadQuantities/m-p/258823#M33840 <DIV class="actalk-migrated-content"><T>Hi there, <BR /> <BR /> When I am exporting the object to and IFC, I am getting a difference in the quantity values.<BR /> e.g. One external wall, I have the .NetSideArea 7.6311 m2, and in the ArchiCadQuantities the Surface area is 7.8726. Which one is correct, and why there is a difference, how are they calculated?<BR /> <BR /> Thanks in advance.<BR /> Fiona</T></DIV> Mon, 05 Nov 2018 13:20:52 GMT https://community.graphisoft.com/t5/Collaboration-with-other/Difference-between-Base-Quantities-and-ArchiCadQuantities/m-p/258823#M33840 Anonymous 2018-11-05T13:20:52Z https://community.graphisoft.com/t5/Collaboration-with-other/Difference-between-Base-Quantities-and-ArchiCadQuantities/m-p/258824#M33841 Hi,<BR /> <BR /> I am not sure what the IFC value measures (I suppose the actual area of the 3D body on one side). Take the 3D model, start measuring it, and see which measurement might match the IFC value.<BR /> <BR /> For the ARCHICAD value though, <A href="https://helpcenter.graphisoft.com/?p=76908" target="_blank">here's a complete list of all the wall area parameters</A> you can list, with pictures. The General Surface Area parameter should measure the area of 'reference line'*'height' in case of walls.<BR /> <BR /> Regards, Sat, 10 Nov 2018 10:28:47 GMT https://community.graphisoft.com/t5/Collaboration-with-other/Difference-between-Base-Quantities-and-ArchiCadQuantities/m-p/258824#M33841 Daniel Kovacs 2018-11-10T10:28:47Z