# Extract footprint from mass **URL:** \ **Category:** Geometry\ **Created:** [December 9, 2016, 10:09am UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123 "2016-12-09T10:09:27Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Tchunoo\_Rhee\_Kahng](https://avatars.discourse-cdn.com/v4/letter/t/edb3f5/32.png) [@Tchunoo\_Rhee\_Kahng](https://forum.dynamobim.com/u/Tchunoo_Rhee_Kahng)\ **Post date:** [December 9, 2016, 10:09am UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/1 "2016-12-09T10:09:27Z")
Im trying to implement a method which can easily show the footprint of a mass. The revit mass dynamically updates gross floor area, but not footprint, so i attempted at a graph that would do so. ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/8/b/8b5d4efdbc135e7d60111348437d3bbe5c22f373.png) ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/a/fadb0836f9f48d2e099863452bfc74c2d56d69d2.png) The graph takes all surfaces from the geometry, filters surfaces that have a normal vector of 0 to account for sloped surfaces. After this i am sort of stuck. I wish to project the surfaces to a plane, merge them, and extract the area of the new surface. However i could not find nodes that would facilitate this workflow. Abother attempt was to extract the curves of the surface, project them to a plane, eliminate coinciding curves to create a boundary, surface by patch it. Howver again i could not find a way to eliminate coinciding curves. If anyone has experience with footprint extraction of geometries, i would appreciate some tips and assistance. Thanks in advance. ---
**Author:** ![Kulkul](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/kulkul/32/49801_2.png) [@Kulkul](https://forum.dynamobim.com/u/Kulkul)\ **Post date:** [December 9, 2016, 10:45am UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/2 "2016-12-09T10:45:29Z")
Hi @Tchunoo_Rhee_Kahng Here is one of the possible way to get mass bottom surface. ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/c/0/c0b7dd12cd25885d886ba59c0c523a5ad233d2a8.png) ---
**Author:** ![Vikram\_Subbaiah](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/vikram_subbaiah/32/50797_2.png) [@Vikram\_Subbaiah](https://forum.dynamobim.com/u/Vikram_Subbaiah)\ **Post date:** [December 9, 2016, 2:12pm UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/3 "2016-12-09T14:12:25Z")
@Tchunoo_Rhee_Kahng Ensure there is a level at the base of the mass and a corresponding Mass Floor, you can then do something like this… ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/1/f10a4eeb7f301ec62e677e08d8c6f1004b613616.png) Also, the nodes in your screen shots abbove aren’t clear. zoom in until the text in the nodes is visible before you capture the screen in Dynamo. The entire graph is captured even if it isn’t visible on your screen. ---
**Author:** ![Tchunoo\_Kahng](https://avatars.discourse-cdn.com/v4/letter/t/ecd19e/32.png) [@Tchunoo\_Kahng](https://forum.dynamobim.com/u/Tchunoo_Kahng)\ **Post date:** [December 11, 2016, 8:34am UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/4 "2016-12-11T08:34:41Z")
@Vikram_Subbaiah @Kulkul thanks for the response guys!! I believe i have not articulated my question. I want to figure out the Building Coverage of a mass with a “Footprint(touching GL)” is not equal to the Projected Boundary in Site Plan. So i just want to find the “Site Coverage” of a Mass. ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/d/f/dfd24d59eb82f54e1665c5542e080f94dcd4a6b2.PNG) ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/6/06ec132ce84dc14145b76ea2f8378aed0145cb1d.png) and @Vikram_Subbaiah thanks for the tip on screen shots, I always wondered why my caps were so fuzzy. I hope this can clear up some confusion. ---
**Author:** ![Yna\_Db](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/yna_db/32/30641_2.png) [@Yna\_Db](https://forum.dynamobim.com/u/Yna_Db)\ **Post date:** [December 11, 2016, 6:49pm UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/5 "2016-12-11T18:49:38Z")
Hello, this outer boundary method could probably help: [Get an outer boundary of multiple polygons (Room Boundaries)](https://forum.dynamobim.com/t/get-an-outer-boundary-of-multiple-polygons-room-boundaries/7177) ---
**Author:** ![Vikram\_Subbaiah](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/vikram_subbaiah/32/50797_2.png) [@Vikram\_Subbaiah](https://forum.dynamobim.com/u/Vikram_Subbaiah)\ **Post date:** [December 17, 2016, 2:10am UTC](https://forum.dynamobim.com/t/extract-footprint-from-mass/8123/6 "2016-12-17T02:10:51Z")
@Tchunoo_Kahng My above suggestion should work. Assuming _Level 1_ is footprint level, extract the mass _Floor Area_ of _Level 1_ In the example below the base of each block is 100sqm, the resulting Mass _Floor Area_ parameter reads 200sqm ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/f/7/f74d3645b585bfa779d6f69dc752f6de1c08f7dc.png)