Rhino on large scale project #1: What is Worksession?

The larger the scale of the project, the more ingenious the way of creating the model needs to be.
If you build a single file without thinking about it, you’ll end up with certain situations such as;

  • Too heavy to open
  • Multiple people can’t work at the same time

So, basically, the way to operate is to

  • Split the model and save them
  • Change the import file range as needed

For Rhino, if you want to associate multiple split files, you have the choice of Worksession or LinkedBlock.

Each has its own pros and cons. This time, I will write about Worksession.

What is Worksession?

Let’s start by explaining what Worksession is.
First of all, please read the original document.


https://docs.mcneel.com/rhino/5/help/en-us/index.htm#commands/worksession.htm?Highlight=Worksession

Did you read it?

Let’s take an example, assuming data of a curtain wall.

I envision a team of two people modeling exterior construction.

Once the main lines of the allocations and fastenings are established, and the hardware and sash details are created, the data becomes heavy.

Let’s assume that they are modeling with the following personnel structure;

  • A is in charge of fasteners
  • B is in charge of the panel

First, create the following three 3dm files.

  1. Grid, subdivision lines, and steel frame
  2. Fasteners
  3. Exterior panels

A opens the file no.2, which A is in charge of. A also needs information on the subdivision lines and the frame.
So, for the first file, A uses Worksession.

When using the command, a Worksession dialog will appear.

Press the Attach button.

If you want to make it more intuitive, you can do the same thing by dragging a file into the Rhino window and selecting Attach from the menu that comes up.

It is also possible to right-click on an empty space in the Layers panel.

You can now edit the second file while referring to the first file.

And let’s refer to file #3, which is also a work in progress.

You can also save the file A.rws by going to Worksession>Save in this state.


The rws file is not a modeling, but a storage of relationships among multiple files.

Double click on A.rws to open file #2 and read files #1 and #3 as references.

A.rws does not contain three 3dm files.

Similarly, B can create B.rws that reads number 3 as the target of editing and number 1 and 2 as references.

The good thing about Worksession is that it can be cross-referenced.

(For external references in AutoCAD, the reference relationship between fasteners and panels needs to be one-way.)

Also, keeping the grid and reference lines in a separate file will help prevent accidents such as “I accidentally moved it”.


A and B can refer to each other’s modeling as they work.


In this article, I explained how Worksession can be used to share the workload.

Dividing the file into smaller units (e.g. panel-by-panel) opens up new possibilities.


In the next article, I will show you a batch process that can be made possible by separating each panel into a separate file.

Translation: Yukie Takasu

takahiro.ishihara

Mainly working on façade and parametric modeling. Previously worked as an architectural designer at AEC firm. Write about complex geometry and model with information from CMr / PMr viewpoint.

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