Components - Instance and definition

I saw this video a while back about the above subject.
(Instance or Definition - Square One)

To have an additional question.
I understands the difference, but then how to use them in an organised way to use them in a report?

Let’s say I got a wooden frame, using SLS wood with a size of 38mm x 140mm. Lengths will be vary.

Bottom and upper Plates each with a length of 3000mm
Studs 4 pieces of 2700.
2 headers of the same material/ size with a length of 600.
2 Shorter King Studs of 2500mm ( header support )
2 Shorter Trimmer Studs of 2000mm ( window support )
1 Sill Plate
2 Bottom and Top plate

All copied from a component named SLS ( resp: clone or unique copy )

Now I name them like this.


Definition name      - Instance                        - Applied to

SLS                  - Studs                           - 4 pieces of 2700mm
SLS#1                - Cripple Window Support          - 2 pieces of 2000
SLS#2                - Trimers Header Support          - 2 pieces of 2500
SLS#3                - Header                          - 2 pieces of 600
SLS#4                - Sil Plate                       - 1 pieces of 524
SLS#5                - King Stud                       - 2 pieces of 2700mm

Looks okay to me.
But then the opposite wall has a different Stud size, like 38 x 85.

How should I continue? With the naming? I know, many variations possible, but curious how you people do this?

At first I don’t like to put in the definition the size Like “SLS 38x140” and “SLS 38x85”. This because If I change the SLS size from 38x140 to 38x120 then I’am busy with…

This all in mind to use it in the SU report generator and of course with al lot more different kind of components.

If it were my project I would use your instance names for the definition names and the instance name to identify individual instances if that’s actually important to whomever will be using this report.

How do the definition names in your model provide useful information to your audience? If I’m building that wall I want to know how many studs, cripples, headers I need to cut. ‘SLS’, ‘SLS#1’, ‘SLS#2’ doesn’t tell me anything useful and looks like clutter.

I’d also prefer to see the quantity in the first column and only the length in the last column. I would include thickness and width of the parts. If the thickness is the same for all of the timber, I would sort the rows by timber width to reduce the chances of errors.

Just tell me how many sill plates and studs there are and give me their lengths.

Here’s part of a cutlist from a recent project. Obviously not walls but the idea is still the same.


Organized mainly in the order the parts would be needed for assembly but also by width and then length.

When I’m in the shop cutting these parts I want to make sure I get the longest pieces cut first to make sure I get the most efficient use of the materials. I don’t have to scan the list to see which parts to cut. I can also easily see which parts can be batched together for ripping to width so I can reduce machine setup time.

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Thank you very much for your reply.

I forgot to mention, that the report export is used in excel and from there I calculate what I need + cost to order the whole bunch.

I want to have a key from the report that will be used to lookup into a materials table.
For example with the SLS wood, now I do use the Definition Name + Thickness + Width + Length ( Rounded to the nearest Higher length ) then do a QTY sum calculation of the new length and then that using the price of 1 Unit length ( m ) multiplied with sum of QTY.

For cutlists, I use for now the Instance name and make different reports in excel.
The Column order is not an issue in excel.

The problem for me is, I feel definition in SU is misused, in software you use the instance with their attributes data to get your information.