BIMAfterDark Presentation - NURBS in Revit

 Ever wanted to create vegetables in Revit?  No, well, what about curvy furniture?

 Organic Shapes using #NURBS in #Revit.

I will be presenting as a guest speaker on #BIMAfterDark Live (The RevitKid).

•  7.30pm US Eastern Daylight Time 8th October 2020.

Or 

• 10.30am Australian Eastern Daylight saving time 9th Oct 2020. 

• Or watch it later

Here is the link on YouTube Live: https://youtu.be/VUkM7I1tiTs

 

Weird Stuff with Global Parameters in Revit

Following on from my earlier posts about transferring global parameters between Revit projects, and deleting global parameters, here is some quirky stuff that happens when you are working with Global parameters:

Weird Behaviour & Bugs

1.   Duplicate Labelled Dimensions

If you add a dimension to elements that already have a ‘global parameterised’ dimension, the new dimension automatically takes on the same parameter, without you realising.   If you subsequently delete that dimension, you get a message saying ‘A Dimension that is labeled . . .’  Unconstrain to remove constraint

• If you expand the warning, it tells you what the Parameter label is

•  It does not tell you that you are deleting a secondary (redundant) dimension with the same label as another dimension, which still remains in the model

 2.  GP Equals Constraint Conflict – Fixed in v2018 (?)

If a dimension between two elements (say gridlines) has a GP associated to it, then you place a dimension between the grids and an element midway between them, you would expect to be able to change that dimension to ‘Equals’. Illogically, Revit does not allow this – it warns you that it needs to remove the constraint. Unfortunately if you go ahead, it removes the GP constraint but keeps the Equals constraint – which is not very helpful as you now need to guess which other constraint it removed. It does not highlight the other constraint

• I recommend that you cancel, then figure out where the conflict is - do not click on 'Remove Label'
• One solution to this is to create another GP that is a fraction of the original one (half, in this example), and apply that to the secondary dimension, instead of an equals constraint

• Another solution is to put the equality constraints between other elements that are in the same location but not GP dimensioned – eg between two walls that are aligned to the gridlines.
• NB. This problem does not occur if the GP associated dimension is a reporting parameter.
• This bug is reportedly fixed in v2018, but I have not had time to test it yet

3.  Edit Witness Line Bug

If you associate a GP to a dimension, and then subsequently delete the dimension, Revit will ask you if you want to unconstrain (remove the constraint) – this is good behaviour. However, if you edit a witness line instead of deleting the dimension, Revit removes the GP association (as you would expect), but does not ask if you want to remove the constraint – effectively hiding the constraint. This is really bad behaviour by Revit, because it means you can end up with lots of hidden constraints, which catch you out later on. Autodesk refuse to accept that this is an inconsistency in the software that should be changed. I recommend that you never edit a witness line on a GP associated dimension.

4.  Shape-Handles vs Calculation

If you have a family that has grip handles when placed in the model, those handles can be ‘hidden’ when GPs are associated with certain properties in the family. This happens if the property is used in a formula that drives the geometry related to the shape-handle:

• No GPs associated – shape-handles available

 

• GP associated to a property used in width formula

• In this situation, it is better not to associate the GP directly to the property. Instead you need to use a dimension with a reporting GP associated to it. Then the association is far enough removed so the shape-handles are unaffected.

5.  Circular Chain of References

• At some point you are likely to encounter this warning dialog:

 

• I strongly recommend that you do not click on ‘Resolve’ because it will remove a formula, but not necessarily the one you are expecting, nor the one you just added that caused the problem. Instead you should cancel and figure out what is causing the problem – first click on ‘Expand’ to see if you can figure out the conflict; although using the ‘Delete Checked’ option does not seem to resolve anything (the same dialog just as likely pops up again), so you will then have to cancel anyway.

6.  Change Instance to Type

If parameters are changed from instance to type in a family, then reloaded into a project, you may get this message if the parameters had been associated to GPs

• You then have to reassociate the property to the GP – but it is easier to do as it is likely to be only one type property to relink

7. Duplicate Type Loses Associations

If you duplicate a family type that has GP associations to any type properties they lose the associations.

Applying colours and Materials in Rhino for Revit Import

Following on from my previous post about importing Rhino materials in Revit 2017.1   here is a brief description on how to set up the colours/materials in Rhino:

I am new to using Rhino, so my understanding of the UI and functions is pretty basic but I managed to figure out how to apply colours and materials to objects without reading any manuals.  I am happy to be corrected if there are better ways to do this.

Once you have created an object (or multiple objects), you can select the object and view its properties.  Unless you tell it otherwise, it will be on the 'Default' layer, with Color, Linetype etc set to 'By Layer', which means that it will behave according to the layer settings.  During the new import process, Revit 2017.1 considers the default layer & colour not to be a material.

 

You can change the layer of the object from the Layer drop-down list, providing you have created new layers

By default, your file most likely will have no layers, so you need to create them, using the 'Edit Layer' function, available from the Edit menu.

Once the layers menu has been opened, it will be available under a Layers tab.  It has typical columns showing the name, show/hide, lock, display colour (just a box) and material properties for each layer.  New layers will have default settings (no colour or material defined), but these can be changed by clicking on the colour box or adjacent space under the material column.

If you are creating layers just to manage export to Revit, the names are irrelevant to Revit, but the colour and material are important - you don't need to get the colour/material right for its end use in Revit, as long as each object has a different colour, it will become a different material when imported to Revit.  The materials can then be edited in Revit.

If you expand the width of the menu it shows the material name (if defined), linetype and print width/colour - the print colour does not seem to be relevant for Revit imports.

Materials

You can define a material for use in Rhino, but the only thing that Revit takes note of is the material colour.

Rhino Material Properties

Object Properties

Normally, objects will display according the the 'By Layer' settings, which means that all objects on a given layer can have their properties changed together easily.

Object properties By Layer

You can override individual 'Display Color' for any selected object

Object properties By Object

If you choose a non-standard colour, it will show the colour name as 'Other'

SAT files

I tried exporting a coloured Rhino file to SAT format, then importing it to Revit, but sadly it did not bring the colours in as materials - so I am not sure what the trick is to assigning colours to objects in a SAT file.  I tested various ACIS versions of SAT format, to no avail.

Rhino Export SAT options

Does anyone know how to define colours for objects in a SAT file from Rhino?  Or from any other 3D modelling software?

Import Colours to Revit

For details on how these colours are imported to Revit, refer to importing Rhino materials in Revit 2017.1

• It seems that Revit uses the display colours set in Rhino, not the print colours.
• If you import two different Rhino files that have identical colour definitions, it treats them as different materials
• If you import the same Rhino file twice, it seems that Revit assigns the same materials to objects in both instances
• However, if you rename a material, or change its definition before importing the second instance, Revit will create new materials with a suffix of (2) added to the original name.  You could use this to your advantage if you want multiple instances of the same object but with different materials.