HELP: Open Cutlist - Materials List differs from Cutting Diagram Materials Overview


I’m designing a garden office / workspace and I’m using Open Cutlist to generate a list of required materials.

I’ve defined all the relevant materials e.g. OSB 18mm / OSB 19mm / CLS 4x2 etc and nicely generates a summary list of required materials.

However, when I then generate the individual cutting diagrams, the amount of required materials is often significantly lower than the amount on the summary list.

For instance:


OSB 9x1200x2400mm
Summary = 23 boards
Cutting diagram = 14 boards

CLS 4x2 / 3000mm
Summary = 93 pieces
Cutting Diagram = 57

any idea, what causes that amount of different and how I can get just one correct number?

I’ve attached the sketchup file for reference …


GardenHouse.skp (2.1 MB)

Best to share the model, too

thanks, how can I attach the sketchup file?

attached the sketchup file!

I don’t use Open Cut List but I wonder if it has anything to do with the way you’ve used scaled components to create parts like the shiplap cladding. This is not really a good way to go if you want accurate information out of the model.

I doubt the nesting of these components is helpful either.

Thanks for the reply! Can you elaborate a little on this? I’ve made sure every component that is the same size is unique …

what’s wrong with scaling components?

Apologies if these are very basic questions … I’m new to this …

I also don’t use Open Cut List (OCL), so I can’t analyze any problem specific to it. I’ll just look at your model for general issues that might or might not be causing what you see. Regardless of whether they affect this problem, it’s worth learning about them to make your model better.

There are quite a few instances of “Walls Front - Wide” that have no assigned material. Perhaps that causes them to be left out of certain reports from OCL? Does it organize by material? In particular, could this cause these parts to be missed by a report that uses material to decide whether a part is sheet goods, solid, or something else?

I see three component instances in your model that somehow have a single space as their definition name (see screenshot below).

Screen Shot 2022-01-08 at 9.30.39 AM

Again, could this confuse OCL about what they are? I notice that they have an unnecessary level of nesting, which so far as I can see accomplishes nothing.

Speaking of nesting, I know that the simpler CutList extension reports only the deepest nested (“leaf”) objects; surrounding “parent” groups or components can be used for organizing the report but are regarded as assemblies, not seen as “cuttable” objects per-se. How does OCL handle nesting? Is there a setting that could cause it to report parents as if they are actual “cuttable” objects? Or perhaps to split leaf objects out by parent?

I very much doubt that it is causing your problem, but your use of layers isn’t correct. You have 5 layers that are not being used by anything (maybe you assigned Outer: All instead when doing the cut list?). You also have some edges and faces that have layers assigned. Only groups, components, and non-geometry objects such as dimensions, text, and images should use layers. Assigning them to edges and faces can cause strange and confusing behavior because they don’t prevent edges and faces from interacting, even if they use a non-visible layer.

This also shouldn’t be part of your problem, but you have 15 unused component definitions that could be purged.

Thanks for this! I had no idea about nesting …

how do I get rid of the nesting?

You right-click on a superfluous parent container (either in the view or the outliner) and click “explode”. The only gotcha in this is that SketchUp’s explode will cause everything that was in the previous parent - including edges and faces - to be changed to use whatever layer the parent used. You can clean this up quickly while the contents of the parent are still selected following the explode.

Thanks for that … my issue is that the parent name is actually the correct name. I must have copied a component and made that unique, which caused this parenting …

What’s the correct way of creating components that are similar to previous ones?

E.g. a new piece of wood that has the same orientation (component B), but is 20mm longer than another component (existing component A).

I would have copied component A, made it unique, renamed it to component B and then scaled it.

Is that an issue?

The sequence sounds good to me.

With all this, it is worth while to make sure you understand the underpinnings of SketchUp’s system of “components” because the term is used loosely used to cover the whole concept and the actual bits in play in various operations might not be what you think. This reply may be too technical or TLDR, but hopefully it will help you to appreciate what is going on…

The heart of a Component is a Component Definition. This is like a template that spells out what is in the component. Component Definitions are like abstract objects waiting to be made real. They are what you deal with if you open the Components window.

What you see in the model is an Instance of the Component. That is, a concrete collection of stuff assembled based on the instructions in the Component Definition and placed at a specific location, orientation, and scale in the model. You can pull a new instance of a Component out of the Components Window and drop it the desired place in the model. Or you can create a new Instance by copying an existing one in the model.
Each Component can have any number of Instances placed in the model - including none.

That last point causes bloated models if you experiment with a lot of Components and then delete the ones you no longer need. You actually delete Instances. The Definition remains in the model’s collection. Do that a lot, and you can have a lot of memory being hogged by Component Definitions you no longer need. You “purge” the model either via the Model Info statistics tab or an extension to get rid of the Definitions you no longer need.

There is some slight-of-hand involved in some of the manipulations of Components.

For example, you create a new Component by selecting some collection of items in the model and invoking “Create Component” via your favorite choice of menu, right-click menu, keyboard shortcut, etc. What actually happens then is that a new Component Definition is added, capturing the general structure of what you selected, and a new Component Instance is placed where the selection was. You have the option to skip the creation of a new Instance by unchecking the “replace selection with component” box in the Create Component dialog, in which case you get a new Definition but the original items remain loose in the model. This can happen by default if there are unselected items touching the ones you selected. Forgetting to check this box is a frequent source of confusion to newbies.

When you open a Component for edit, you are actually accessing the Definition via a selected Instance and editing the Definition. That’s why the changes immediately propagate to all the other Instances of that Definition.

Now finally to your question

I don’t see how that would create nesting. “Nesting” means that a Component Definition (the “parent”) contains one or more Instances of other Component Definitions.

When you invoke “make unique”, a new copy of the Component Definition is created and the selected instances are re-tied to that new Definition instead of the original one. You may note that make unique isn’t available unless everything in the selection is an Instance of the same Component.

There is no reason why make unique would create nesting.

I don’t see an issue with the method you describe.

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Thanks for the detailed insight … I’ve tidied up the components using the outliner, that was very useful …

Have a look and let me know what you think!
GardenHouse.skp (2.9 MB)

I’d give some thought to the necessity of the bushes behind the building. They are contributing over 80% of the model edges, over 4000 component instances, and almost 6000 groups with little actual benefit to what I presume is the purpose of the model. You could no doubt get by with something much simpler that conveys the same idea. I imagine, as very often the case, you got them from the 3DWarehouse without knowing about this problem.

Otherwise the nesting structure is considerably cleaned up - essentially flat. I would suggest giving instance names to things, though, as it is quite difficult to decide in the Outliner which instance of, for example, “Wall - Studs - Back - Vertical - CLS 63x38” is which.

You also are still using layers badly. There are about 21000 edges and faces using layers, mainly the Doors and Windows layer. Only groups, component instances, and non-geometry such as texts, dimensions, and images should use layers. There are extensions that can reassign them all to Layer0 (which really amounts to “no layer”) efficiently instead of you having to do them all manually, for example TIG’s Layer Watcher (available free from the SketchUcation plugin store).


Sorry. I was away from my computer all day. Looks like @slbaumgartner has you pretty well sorted so I’ll not add anything that might confuse things.

Again, many thanks for the detailed explanation … point taken about the bushes, yes, it’s something I’ve just downloaded from 3D warehouse. And I had no idea that it would cause issues.

Naming instances, again good point, I was in the middle of building the model and didn’t have time, but definitely something to look into going forward.

As for the layers, what’s wrong with them? I know there are a lot, but I use them to quickly turn on or off visibility of various parts of the model.

Is that an issue if I use them like that? Or is there a better way?

What’s wrong with scaling? I thought that’s one of the main benefits of Sketchup, that you can easily scale stuff …

I explained what is wrong: you have individual edges and faces using layers. Only component instances and groups should use layers other than Layer0.

Nothing if it is done correctly. In your model, however, the way you did the scaling creates issues for other parts of the process. In the case of the ship lap siding for example you have 156 components but they are different lengths. That’s not very useful.
![Screenshot - 1_9_2022 , 6_08_21 AM|690x373](upload://yKBCSMJddbuGa64cOEhWdQndUay.png

I guess I wouldn’t consider it a main benefit of SketchUp. Scaling can be useful when used correctly. Very often, though, Scale is not the right tool for the job. Move or Push/Pull or some other method is the better choice for resizing elements in the model.

In general what I see in your model shows you are working harder than you really need to and creating a model that is more difficult to work with if you need to make modifications and especially if you want to get useful information like a cut list out of it.

@slbaumgartner mentioned incorrect tag usage. I’ll just show the result of fixing that.
Screenshot - 1_9_2022 , 6_26_24 AM
And then purging unused stuff.
Screenshot - 1_9_2022 , 6_26_40 AM

I also noticed issues with the geometry such as at the top left corner of the door. Siding doesn’t meet correctly and the siding is inside the OSB by more than 3 mm.

The misalignments shows at all the joins. It would appear that you deformed the geometry in scaling. Note how the bounding box doesn’t fir the component tightly.

That would account for the softened and hidden diagonals on the faces of the siding components.
Screenshot - 1_9_2022 , 6_22_42 AM|690x317

FWIW, here’s an example that yields more useful infomration and makes the model easier to work with. I’ve omitted the roof in the example.

The cutlist (using my preferred cutlist extension) showing just the siding.

I get useful counts of the various lengths and can see from the list where they go.

I exported a CSV file of the cutlist and did a bit of quick massaging to simplify the report for shopping.

This is based on a garden shed I built about 18 years ago. Glad I don’t have to build the thing today.

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