tag:blogger.com,1999:blog-9240097.post3085966991643872237..comments2021-03-19T09:16:08.610-07:00Comments on Revit OpEd: Voids Voids VoidsStevehttp://www.blogger.com/profile/14230364057800484763noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-9240097.post-49625498941631325332013-03-01T13:08:28.917-08:002013-03-01T13:08:28.917-08:00Erik - I can count on you to add value to any post...Erik - I can count on you to add value to any post!<br /><br />Jeff - Wrote this post thinking - I am poking Jeff in the eye with this one, thank you for the factory insight!<br /><br />A tangent: I often think that the 2D versus 3D being visible in views seems a bit counter-intuitive to think that a file with many more elements - one using 2D lines, masking and such - will outperform one with fewer, but 3D only elements.<br /><br />Seems to me if a family is simpler - has fewer elements - that it should outperform one that is more complicated by adding 2D only elements to avoid displaying 3D forms.<br /><br />Autodesk Seek is quite particular about this and I think it is over generalized.Stevehttps://www.blogger.com/profile/14230364057800484763noreply@blogger.comtag:blogger.com,1999:blog-9240097.post-20686274795321661952013-02-27T12:35:09.648-08:002013-02-27T12:35:09.648-08:00Oops, my math was off in my example above. The do...Oops, my math was off in my example above. The donut form created with the void is 16 faces not 14. The same donut created as a sweep is still 10 faces. Sorry about the math mistake.Jeff Hanson, Autodeskhttp://wikihelp.autodesk.com/Revit/enu/2013noreply@blogger.comtag:blogger.com,1999:blog-9240097.post-46118544606394856642013-02-27T12:15:31.139-08:002013-02-27T12:15:31.139-08:00I can't give a definitive answer to: "How...I can't give a definitive answer to: "How many is too many?" But I can shed some light on the problem since I was in the room when the documentaiton you mention was discussed/authored. When voids are used to create geometry more "faces" need to be calculated which can slow performance.<br /><br />Imagine a simple cube solid form, this form needs 6 "faces" to be calculated. Now imagine a void rectilinear type of form intersecting the original cube leaving a "donut" type solid. Now 14 "faces" need to be calculated. 6 for the original solid, 6 for the intersecting void, and 4 for the resulting interior donut faces.<br /><br />If you make the same exact shape using a sweep only 10 "faces" are calculated. The 6 for the exterior of the donut and the 4 for the interior of the donut.<br /><br />So the basic idea here is the more faces that need to be established the slower things will perform. So using voids to cut geometry will ALWAYS increase the number of faces simply because the faces of the solids and the voids as well as the resulting intersecting faces need to be calculated. In small amounts you will probably not notice the performance hit, but the more voids you use the more chance you have at noticing the performance reduction. Sometimes using voids makes making the geometry much easier tahn if created completly from solids, but they will cause some preformance reduction.<br /><br />I hope that sheds some light on the advice in the documentation. Jeff Hanson, Autodeskhttp://wikihelp.autodesk.com/Revit/enu/2013noreply@blogger.comtag:blogger.com,1999:blog-9240097.post-78882671511386237672013-02-27T09:54:59.055-08:002013-02-27T09:54:59.055-08:00Seven’s the Key Number Here. Think About it. Seven...Seven’s the Key Number Here. Think About it. Seven Doors. Seven-Eleven. Seven Little Chipmunks Twirling on a Branch, Eatin’ Lots of Sunflowers on my Uncle’s Ranch. Seven!Erikhttps://www.blogger.com/profile/05930332092459194929noreply@blogger.comtag:blogger.com,1999:blog-9240097.post-3853855719385400332013-02-27T06:13:09.797-08:002013-02-27T06:13:09.797-08:00At least, in regards to arrays of non-nested items...At least, in regards to arrays of non-nested items, there seems to be a specific number that triggers warnings about performance. That number is 11. Revit never complains for any number of items up to 10. But as soon as I enter 11, Revit shows the warning: "This array contains multiple copies of some identical geometry. Performance might be improved by using a nested family and arraying copies of its instances." The interesting thing is that Revit complains at 11 regardless of the type of object, solid or void.<br /><br />Alfredo Medinahttps://www.blogger.com/profile/06998597439608444010noreply@blogger.com