Pointless stuff, Offset parameter in Revit massing

This article builds on recent posts on the use of Reference point, when working in the conceptual massing environment. The more I use them, the more I realise how powerful they are.

If you place a “Reference Point” and take a look at its Instance properties, you will discover its a System Family.

You can control how it displays in the conceptual environment; for instance you can change the Show Reference Planes Parameter. You are provided with three options “Never”, “When Selected”,  “Always”. You can also control its visibility by enabling or disabling the “Visible” parameter.

Under the Graphics section we can say whether its “Driven by Host” and you will also see an “Offset” parameter. We can also name the point. Lets focus on the “Offset” parameter.

We can drive the offset parameter, thus moving the point by adding a figure into the “Value”. This offset distance is based on the plane the point was originally position on. So if we add 1m into the offset it will move the point 1m in a “Z” direction, assuming it was position on the X,Y plane.

Now the smart thing here is because the point has a total of three planes, XY, ZY,ZX, we can also place points on these planes and drive points using there offset from the planes.

Take a look at the video which should hopefully explain this in more detail.

Autodesk-revit.blogspot and YouTube

Thought you might be interested to know that I now have an YouTube page where you can get access to all my posted videos. Some have voice, others don’t. I wouldn’t say that they are edited particularly well, but hopefully they will be of use to somebody. :-)

http://www.youtube.com/user/davidlightrevit

Helix from lines and points

Following two great blog posts on creating helix’s; one from Buildz blog and the other from BIM troublemaker, I thought I’d run through my solution to this problem. I have been experimenting with this for a few weeks now; not being great at math, I wanted to see if I could create a helix without the need for heavy formula.

Hopefully these two videos will explain my approach; I’ve had to split the the how-to video into two parts, due the 11 minute YouTube limits! They include all the normal mistakes, so don’t expect a super slick video. :-)

If you interested, you can also download the family from here.

BIM Troublemaker

Be sure to check out BIM Troublemakers blog, some cracking formula work here…

http://bimtroublemaker.blogspot.com/2010/02/spring-is-in-air.html

Get the hosted point?

This post comes from experimenting with hosted points on lines and arcs and attempting to create a helical form in the massing environment similar to Zach Kron’s recent post. I guessed that you could do something similar using lines connected to hosted points on circles.

So let go back to basics. Points can be hosted to lines, arcs, splines, circles and ellipses (either reference line or lines). Just draw a line or reference line then choose the point tool and place the point on the line. It will snap to the line and  you will  notice it will change in size and will now include a work plane.

If you select the point and choose properties, you will discover that there is now a hosted parameter. This parameter drives the position of the point and it goes from 0 to 1. “0” being one end and “1” the other end. If you wanted to place the point half way along the line, plug in 0.5, voila the point is position half way along the line.

So lines are straight forward, what about circles or even ellipses? Hmmmmm Ok, go ahead do the same thing, but this time draw a circle as a line or reference line and place a point on the circle. Go check the properties of the Hosted Parameter…. No 0 to 1???? some other weird combination of figures????!!!

So what’s going on here? Well I’m no mathematician, so after a bit of investigation I discovered that points are managed differently on closed elements such as circles. You need to go back to do some math…

So the hosted parameter value for a circle is 2pi

(where pi is 3.1415926535897932384626433832795)

therefore  2 x 3.141593 is equal to 6.283186 radians

So the hosted point can have a value between 0 to 6.28318 depending on where it is on the circle.

So to split the circle into degrees

1 degree=2pi/360=0.017453 radians

With this logic in mind try this, create a circle in the massing environment and host a point on the circle. Go the the hosted parameters, then plug in the following figures and watch the position of the points change.

1. 0 degrees - 0 x 0.017453 = 0
2. 90 degrees – 90 x 0.017453 = 1.570796
3. 180 degrees – 180 x 0.017453 = 3.141593
4. 270 degrees – 270 x 0.017453 = 4.712389
5. 360 degrees – 360 x 0.017453 = 6.28308

This opens up to interesting opportunities and allowed me to create the helix using points and lines along with nested families. I’ll show you how I did this in another post……

Sun VirtualBox

I found this little gem before Christmas. I have been running Virtual PC for Windows for the last 12 months using it to test and try alpha and beta software. It was OK, but I found it a little slow especially in relationship to graphics. I could have gone down the route of Virtual Machine such as Parallels, but then it would required me to get my credit card out and its not something I use all the time on my works laptop.So a bit of Googling and I came up with Sun’s VirtualBox, although I am sure there are others out there as well. This is a free VM, details can be found here;

 http://www.virtualbox.org/.

I found it very easy to setup and within an hour or so I had it working with Windows 7 (64bit) with a Windows Vista (32bit) VM running.

The VM supports Direct X and OpenGL as well as the ability to connect USB devices.It seems to offer many of the features that Parrallels has to offer and it is supported on Windows, Mac and Linux. How bizarre would that be…to run Linux as your, host with a Windows VM running Revit???? So if you are looking for a free VM, its certainly worth trying out.