Monday, 31 May 2010

Controlling Wall Joins in Revit

Sometimes when you are drawing walls that are close together you may find that they automatically join. What you are really trying to do is stop the wall short but it just keeps joining up again. This could be because it is attempting to join to something higher or lower on a different level, or a multitude of other reasons. What ever the reason, you can manually override the wall join.

This is what you want to happen. Stop the plaster faced wall on the edge of the blockwork wall and dont allow it to join.

But this is what keeps happening. The blue grip joins to the centre of the other wall (which in most cases is what you would expect it to do).

The answer to this problem is very simple (but not so obvious to find).

The function is called 'Disallow Join'

To find the tool, hover over the blue grip on the intersecting wall and right click the mouse. From the options choose 'Disallow Join'*

*Note: If you select the wall and not the blue grip this option will not be available.

The vertical wall becomes detached from the horizontal wall and will no longer automatically clean up the junction.

You can now drag the blue grip back and accurately determine where you want the wall to finish.

You will also notice a 'T' shape symbol appears at the end of the wall identifying that this end will not clean-up/join. You can click the symbol to automatically join the wall again.

Monday, 24 May 2010

Aligning hatch patterns on a curved surface

Hatch patterns can be manually positioned on a wall to suit brick coursing or other setting-out requirements. Normally you do this in an elevation view or 3D view using either the 'Move' tool or the 'Align' tool.

If you have a curved surface (like the one shown here), it is not possible to adjust the vertical lines in an elevation view or 3D view with the above mentioned methods.

Here are the steps you need to follow to adjust curved hatching...

To adjust the horizontal lines, select a hatch line in elevation or 3D view.

Select the move tool and manually move the hatch line down until it snaps to the head of the reveal.

The vertical hatch alignment updates as shown here.

If you try this process for the vertical lines it will not work. Instead, select a vertical hatch line.

This time, pick the Rotate tool and you will see snaps appearing if you hover over the base of the wall as shown. Click on the end point at the reveal to adjust the vertical placement of the hatching.

The vertical hatch line will update to the new location.

Thursday, 20 May 2010

Revit 2011 Tree Support using Adaptive Components

A simple short video from David Light covering the basics of the new Adaptive Component Family in Revit 2011. Also, check out his blog here

How to recover a central model from a backup

If you use worksets and central Revit models you will notice that you no longer get the 3 or so backup files which usually appear alongside the current file. Typically your browser folder would look something like this -->

If you enable worksets allowing multiple users to access and share the same Revit model, you will notice that these rollbacks (or backups) no longer appear.

On a workset enabled model, by default Revit stores 20 backups of the central file but it is not possible to see or access these backups like the single user file.

To rollback to an earlier version of your central file you must use the following steps...

Without any Revit project open, go to the Collaborate Tab > Restore Backup
Browse to find your central file and look for the folder which has the suffix of _backup (this is usually in the same folder as the central Revit file).

Double click to open and view the contents of this folder (but notice that nothing is in there?).

Ignore the fact that nothing is in there and click ‘Open’.

As if by magic… it opens up a dialogue box which shows the save history. It shows the date and who performed the save. In the example below I used some fictitious usernames as an example. You can see that the last save was performed by revit.user No.2 at 16:29

To preview an archived version you can simply select the version and click ‘Save As…’ and it will make a new independent model where ever you choose.

To make permanent changes to the ‘Live’ central file, use the ‘Rollback…’ button but BEWARE… this change is permanent and you will loose any changes made beyond this date.

If 20 rollback versions just aren’t enough for you, you can change this to another number (but be careful as this will increase the file size of the backup folder).  Example: Consider how many users will be working on the model and how many times they will be saving to central each day.  If you want to be able to roll the model back to the previous day, you will need to make sure your backups are more than the average daily Saves to Central.

Open your local copy of the central file and click ‘Save As…’ In the dialogue box click ‘Options’ (bottom right) and change the number of backups to suit.

Don’t bother changing the file name, just click save. If it tells you this file already exists, you can just overwrite it. That’s it done! The information is sent back to your central file and the number of backups to retain will be updated.

TIP: I would recommend the project BIM coordinator recreates the central file at least once a week.  You will notice the file size is reduced and it will be less prone to crashing - dont ask me why, it just works ;-)

Wednesday, 19 May 2010

Autodesk Labs: Solar Radiation Technology Preview

Autodesk Labs have released the Solar Radiation Tool for Revit 2011. If you didn't use it in 2010 then its well worth a look at this video to see what it can do. You can download it here Autodesk Labs

Components for Existing Building Surveys in Revit

Using Revit for Surveys: A different approach to modelling in Revit is required when it comes to existing buildings. For instance, depending on the age and design of the building, a site survey would probably result in no two windows being exactly the same size. This raises the question “Should I create window types for every existing window?” Depending on the size of project and the scope of works involved this could mean hundreds of types. Consider what the purpose of the survey is and how the windows will be manipulated in the proposed design i.e. Are the windows being replaced? or just generated for model integrity and aesthetics? There could be numerous outcomes.

Example: Instance Based Window Family

One of the methods I have used to combat this with items such as doors and windows is by generating families with instance-based parameters. In the following example we take a look at a typical window family and how we can change the way it works to in a measured building survey.

In this example we start with a window family from the standard Autodesk Library called ‘Sgl Plain.rvt’

If we want this to be an instance-based window family (i.e. able to control the width and height without having to create a new instance every time), then we need to change the parameters from Type to Instance.

Ok, so we have hit our first problem. The standard Autodesk Window category will not allow you to ‘Modify’ the Width or Height parameters so how can we change this?

…Well here’s a little work around:

In 2010 or 2011, Go to the Create Tab > Category & Parameters and set the category as something such as Generic Model and click OK.

Now go back into the Types and you will notice that the Width and Height can be modified.

Change Rough Width & Rough Height to Instance Parameters first, then the Width & Height. Now go back to the Category & Parameters and set it back as Windows.

Tada!   You now have an instance based window!

The example I have modelled here has a few additions to make the survey modelling process a little easier:

Reveal Setback:
More often than not, building surveys require both an internal and external measured survey. The external width of the window is measured from reveal-to-reveal, and also the inside edge from reveal-to-reveal. There is always a difference between the two measurements due to internal plasterboard or other finishes. I call this tolerance the ‘reveal setback’ as shown here.
This is also modelled as an instance parameter so the user can stretch these to suit each individual window.

Another key point to remember is that it is very awkward to stretch the windows when their origin is set to the centre. For survey windows I would recommend changing the origin (setting out point) to the left or right hand external reveal. You can do this by looking at the element properties of the reference plane and checking ‘Defines Origin’.

Splayed reveals:
If you need splayed reveals (internally or externally), you will need to delete the default opening which is located on the back face of the window.

If you do this, you will no longer have an opening in your wall so you will need to create a void extrusion or sweep to create the desired window shape (this is required for any customised reveal opening).

In my example I have used 4 Extrusions: 1 for the external opening width, 1 for the internal and two triangular fillets for the splayed reveals. Depending on your requirements you may want to change how you do this.

I have also removed the cavity closer parameters and wrapping parameters to reduce the file size and make sure the parameter list is not looking overcomplicated.

TIP: Create a Default Wall Material and set the colour to grey and transparency to 50%. This will make it much easier to see what is going on with the 3D geometry as it passes through the wall.

As with any modelling program there is more than one way to approach a task like this. Other ways would include modelling windows as ‘Create In-place’ objects, or just using the normal ‘Type based’ windows. In-place would be my second choice but remember these aren’t reusable in other projects and they will mean you have to start from scratch every time! Type based windows can be used in some instances but just be aware of how many different Types you will need to create. If you only need 5 – 10 Types then maybe this is the better option? My experience would be that if you have a basic kit of instance based survey windows, doors which can be used in most situations, this is the most efficient and productive way of generating survey models again and again.

If you have any other suggestions for building surveys I would like to here from you.

Here is the sample Revit Family rfa file used in this blog. It’s modelled in Revit 2009 so any legacy Revit users can also view it.

Sample Revit Family: Survey-type Window Sgl Plain-IntSplay.rfa

Tuesday, 18 May 2010

Simple Curved Glazing in Revit Curtain Walls

By default, Revit uses straight panels resulting in faceted glazing when drawn around a curve. One method you could use to create this would be to use the conceptual modelling tools to create complex curved geometry.  An simple option which is often overlooked in Revit is to use a basic wall style:

Here is a basic curtain wall with the system panel glazed making it faceted around the curve.

Start by creating a basic wall style which has a single layer 6mm thick and set the material to Glass.

Pick the Curtain Wall System and edit it's Element Properties. 

Set the default panel type to be the new basic wall style.

The 6mm Glass basic wall style will follow the curve rather than being faceted.

Other suggestions for this technique would be to create cladding panels as basic wall styles.

Tuesday, 11 May 2010

Best Practice Content Creation Guidance

So today I've been writing a Content Development Strategy for a company wishing to manage the way in which their Revit Families are created.  The strategy document outlines best practice workflows, how to identify suitable content coordinators/developers and assess training needs etc...

One of the freely available guides I refer to quite often is Autodesk's Revit Model Content Style Guide

The guide is a downloadable zip file (40mb) containing excel documents, pdfs, example Revit Families and check lists. 

If you are looking to set some standards in your office for best practice Revit Family creation, I would certainly recommend looking through this kit.  There are parts which I would debate (as with all guides), but generally it does give you an idea of the key topics which need addressing when creating your own content.  On the whole its a great starting point for BIM Managers or BIM Coordinators to start out from when setting up Revit Family Creation Standards.