Tuesday, 18 September 2012

Revit curtain wall Mullions

This blog is a continuation of:

Curtain wall mullions are made of profiles. I always say during trainings that if you can create good profiles in Revit you have made a big step in modelling.

First you have several different mullions for different situations. This blog will focus on the Rectangular Mullion first.

Curtain Wall Mullions
Circular Mullion
L Corner Mullion
Quad Corner Mullion
Rectangular Mullion
Trapezoid Corner Mullion
V Corner Mullion

Be aware that a mullion is a system family!

Type properties of a rectangular mullion
  1. Profile - if you leave this to default the you can set the value of 2 and 3
  2. thickness is measured from the location line of the curtain wall and equal on both sides. This means that when you draw a cw that mullion is 75 mm thick on one side and 75mm on the other. 
  3. Here you control the width of the mullion and whether it is symmetrical. The total width for this one is 50mm
Personally I only use this default profile if I create interior curtain walls. If I need an exterior curtain wall I want a profile that is completely at the outside of the curtain wall. I do this for the following reason. Often an exterion curtain wall runs in front of a floor edge. If I change the mullion size thickness to a greater value I do not want the mullion to go suddenly through my floor.

How to create your own mullion?
  • Mullion creation rules: you may only put one closed loop into a profile
  • Model only the exterior lines
  • Keep it simpel
  • Keep the amount of line segments in the loop to the bare minimum
  • Do not draw lines on top of each other (it's not autocad)
  • If you need more detail add a detail component
goto Revit --> new --> family --> Metric Profile-Mullion.rft
This template is nice because it tells you where is the outside of the curtain wall.
Next create the following reference planes dimensions, parameters and family type.
Draw a rectangle over the reference planes. In this family you do not need to lock the lines. Revit has a system build in that is called assumed relations. Basically this means that when you draw something to coincide with something else that this can not be a coincidence and you will probably want this to keep coinciding. Sometimes this is nicknamed the feminine side of Revit...
Load into project, since I don't save this file it will come into my project named: family#:60x180mm uder the profiles in the project browser. I will rename this family to Rectangle_outside:60x180mm
(left of the : is the family name and at the right side is the type name)
For profiles I tend to name them according to their shape and purpose / location. (feel free to use your own)
Next create a new type under rectangular mullion.  I tend to give the mullion name the same name as the type name of the profile I am going to use. So in this case I call the mullion 60x180mm
Go to the type properties of the mullion you have just created. (right click it)
Select the profile you have created. All the other parameters should make sense to you. If they don't, change them and watch the result.

Now that you have created your own mullion from your self made profile it's time to use this mullion in a curtain wall.
This will make the curtain wall look like this. (this is the lower left corner of the cw)

Example of different use of a curtain wall
The trick is in the profile
 Use this trick for the length of wall, notice the center and pattern offset
   If you change the wall by the cutprofile. Notice the result.
 Openings also behave slightly different
This is the profile and here you can see where the 1240 and the 620 comes from.

Go to this blog: (link will follow later) for how you add a detail component to a profile to see the all the the lines of a typical aluminium mullion

Revit curtain wall magic

In order to write down as much as I know about curtain walls I have separated  the elements into different blogs. There is a link at the bottom to the next one.

Always when I give Revit trainings I spend a lot of time explain the power of curtain walls. The standard Revit books I have seen are always a bit thin on the subject. In order for students and other people who are interested I'll write out what I tell. This way they can read about it.

Curtain wall basics
First you need to know that a typical curtain wall exist out of the following elements

  1. The curtain wall
  2. Curtain wall grids
  3. Curtain wall panels
  4. Curtain wall mullions

type properties of a curtain wall

  1. Wall function - very usefull for filtering your views. You won't right away see untill you need a way to show the difference between interior or exterior walls in a view. (or one of the other functions)
  2. Automatically embed - You need this if you want to use a CW as window or a door. This will cut a hole in the wall you place it in.
  3. Curtain Panel - here you set what kind of filling you want in between the mullions. Basically you have three options. See section panels below.
  4. Join condition - here you set which mullion has the right of way. (which one is allowed to continue and which one has to stop. (see mullion connections below.
  5. Structural material -  as soon as I figure out how you ungrey this parameter I'll let you know. (Althought I very much doubt you want to use it)
  6. Vertical grid pattern -  here you can set whether you want a pattern and if you do how it should be modelled. Be aware you need a gridline to place a mullion. 
  7. Spacing - In the image the spacing has been set to 3000mm so the vertical gridlines will be placed 3000mm apart
  8. Adjust for mullion size - see image. Basically when you turn this off the bottom and top panels are smaller than the other panels.
  9. Fixed number - when you set this parameter to fixed number then the spacing parameter gets grey out and that parameter becomes an instance parameter. This enables you to create the same curtain wall type but have a different amount of horizontal grid lines per wall.
  10. Spacing - is greyed out and controlled by an instance property
  11. Adjust for mullion size - see image. Basically when you turn this off the bottom panels at the vertical borders are smaller than the other. 
  12. In the first image there is an arrow pointing to where this mullion is
  13. In the first image there is an arrow pointing to where this mullion is
  14. In the first image there is an arrow pointing to where this mullion is
  15. In the first image there is an arrow pointing to where this mullion is
  16. In the first image there is an arrow pointing to where this mullion is
  17. In the first image there is an arrow pointing to where this mullion is
Instance properties of a curtain wall
  1. Number - Only available if you have set layout to fixed number, this sets the number of gridlines in the vertical or horizontal direction
  2. Justification - With this you control where you want the fitting piece placed
  3. Angle - With this you can rotate the gridlines
  4. Offset - With this you can offset the entire pattern by a value. You can increase or decrease the size of a fitting piece.
Next blog is Mullions

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Monday, 17 September 2012

Project North Thrue North with shared coordinates

Here we go again... I have written about this subject in Revit before. I have written that I am quiet fed up with how Revit handles it and so I have said True North it is. No more rotating...

Ofcourse it's not all black and white. Recently during a Revit Structure training the subject got to the table again. Ofcourse this question came after I had setup the project base point. Not surprisingly things didn't go as planned.

In order to try and explaining it I went on to show the odd behaviour of rotating either project north or true north. It's my conclusion that you don't want to use these tools after you have setup the project base point. So far I have only been able to get it wright by using the wrong setting... True north is project north and vice versa. That's no way of working so let's try to get it right.

After a bit of testing it seems that if you do the project north before you link the first dwg things go right.
Original post: http://danielgijsbers.blogspot.nl/2012/04/revit-shared-coordinates.html
In red are the steps extra for Project north True North

Steps: Autocad
  1. open the dwg from the site
  2. choose a easily recognizable point as a project basepoint
  3. use the ID command in autocad to find it's xyz values
  4. create a symbol, I prefere a circle with a cross, and place that ontop of the choosen point
  5. move the symbol to the nearest round value (important because of rounding in Revit)
  6. This location is going to be the project base point
  7. copy the ID value of this point and paste it into notepath
(24 July 2014 because of new insights I suggest you don't use Project North and True North at all!) USE a scopebox if you want to draw orthogonal!)

Steps: Autocad for getting true north setup properly
  1. Take or draw a line in Autocad that you want to be horizontal in Revit
  2. Dimension the angle of this line with a true horizontal line in Autocad
  3. Rotate the line, that is going to be horizontal in revit, to such an angle that it is rounded at the third digit behind the comma. (normally this should be fine enough)
Explanation: you migh have a line that is at an angle of 20.52045493°. This number will give trouble in Revit. You can't use that number in Revit. It will round it down for you. I like to have controle over this therefore I do the rounding. I would rotate this line in Autocad to be at 20.520°. 
If that is not precise enough round it maximally at the 6th digit: 20.520455°. 

To give you an idea of the precision you are dealing with. If you draw a two lines that are both 1000 meters long and you rotate one of them to 20.520 and the other to 20.52045493° the ends of those lines are 7.9mm apart. If you would use 20.520455 the the ends would be 0.00000122mm apart. (For the metrically challenged people, an inch is 25.4 mm)

  1. Copy the rotation value of this line and paste it into notepath
  2. Save the drawing
Steps: notepath
  1. Be aware most coordinate system are in meters and Revit models tend to  be build in mm.
  2. This means you need to move the comma 3 spots to the right
Steps: Revit
  1. Open your level that has a Z value of zero
  2. Goto visibility and graphics
  3. Goto the site category, expand and turn on survey point and basepoint
  4. Select the project base point (the circle)
  5. Copy the X value from notepath into the E/W
  6. Copy the Y value from notepath into the N/S
  7. Copy the rotation value to the: 'angle to true north' value
Do not paste these values into your instance property window, you will get an error. If you paste them into the on screen thing it will accept those values.

Be aware you survey point will move away from your project base point. The project base point is still located on the Revit origin!

If you take a look at your survey point you should see that it's values are all zero. Your autocad origin (0,0) will be lined up with your Revit survey point.

Steps: Revit
  1. Goto Insert --> link CAD
  2. Choose the dwg with the site information
  3. Set Import units to the meters (assuming it has been drawn in meters)
  4. Set positioning to by shared coordinates
  5. press okay and you will get the next message
This is actually good because this should import the dwg origin on top of your survey point. This should also have the effect that the project base point marker you created in Autocad lands ontop of your project base point set in Revit.

Steps: Revit
  1. Pin the dwg. (it seems to behave better when re opening the project.)
  2. Goto visibility and graphics and turn of the survey point this will enable you to use zoom extends again
  3. draw two model lines in this view on top of Autocad lines
  4. Save the revit file and make an export the nwc
  5. Make sure that within the Navisworks export settings you set export to shared coordinates (do not use project origin)
  6. Make sure that within the Navisworks export settings you set the units to feet... (yes really!!!)
Steps: Navisworks
  1. Attach the dwg (the one you linked earlier into Revit)
  2. Attach the nwc from Revit
  3. take a look at the lines you drew in Revit and whether they line up with the Autocad lines. If they do you are good to go!
  4. if you select the revit nwc file and right click it and go to units and transform you should get a dialog box with coordinates that are the same as the coordinates of the project base point in Navisworks. (nice to check) 
  5. If they don't check the steps and all the file and unit settings and adjust them accordingly where needed. If you still have problems contact me.