In Part 1 of this series, I discussed the optimal hardware for SketchUp performance, and in Part 2 I discussed some user interface options you can set to speed things up. In this post, I’ll discuss the modeling process that will allow you to keep performance at its peak, for any size model. Specifically:
- Using components and groups
- Using layers
- Hidden geometry
The model below has millions of faces, which means that SketchUp can be a challenge to just orbit, much less edit. (To check a model’s object count, open the Model Info window, Statistics page.)
But for me, this model is smooth-as-silk to work on. Here’s why.
Components and Groups
SketchUp loves organized geometry. Geometry in SketchUp – all of your faces and edges – must be made into groups or components. The best modelers leave not a single object in their models that aren’t part of either a group or component.
Both a group and component take a set of edges and faces and “wrap them up” as a single object. This makes it easy to select, move, rotate, scale, or hide multiple objects at once. This also prevents geometry from sticking to, or otherwise affecting, other geometry.
Components have the added benefit of repetition: you can copy a component (a shrub, window, street lamp, wood plank) a hundred times or more, and it will have a minimal impact on performance. Try this on “loose” geometry, and you get thousands of objects that add to SketchUp’s poly count, slowing things down immensely. Plus if you edit one component, all copies of that component will update.
The 6+ million faces of this model are organized into over 34,000 components and groups, ensuring that SketchUp will perform smoothly.
For complex models, groups and components are not optional – consider them mandatory. And just as important: you can organize groups and components within groups and components. This is called “nesting,” or sub-groups and sub-components.
There’s a great book by Alex Schreyer on all of this: Architectural Design with SketchUp: Component-Based Modeling, Plugins, Rendering, and Scripting. It’s one of the best books out there on SketchUp modeling: succinct and detailed.
Like most CAD applications, SketchUp has a layers feature. And if you want to model efficiently, using layers isn’t just recommended, it’s a commandment.
In other CAD and photo editing programs, layers control visibly and the order of appearance, and objects can reside on more than one layer. It’s a little different in SketchUp: layers control visibility, and therefore performance. And an object can be on only one layer, though you can get around this by using groups and components, if you want to get complicated. (See Bonnie’s post on layering best practice, and my post on some layer case studies.)
If you have a lot of trees in your model, having them displayed all of the time can cause major display delays, not to mention that trees can get in the way of other things you need to model. So create a layer for trees and throw all trees on that layer. That layer can be turned off, hiding the trees.
With layers, you can add tons of detail to a model and toggle things on or off as needed. And you can save views with specific layers showing, by using scenes. This is essential when working with LayOut and creating models for construction documents or BIM. So everything in your model should be a components or group, and every component or group should be on an appropriately-named layer.
This model has an incredible level of detail, including interiors, seating areas, lighting, cars, people, etc. But with everything on its own layer, it’s easy to display only what’s needed in a particular view.
Have you ever downloaded what seemed to be a simple model from the 3D Warehouse, only to encounter performance issues? When this happens to me, the first thing I do is turn on all layers and display hidden geometry (menu: View / Hidden Geometry). Then I click Zoom Extents, to display the entire model. Most of the time, this will unearth hidden objects. Then I go in and start deleting things, which can be tedious, to say the least.
Look at all the hidden objects in this model – so much to delete….
Unlike objects on hidden layers, un-layered and hidden geometry is still processed by SketchUp when orbiting, zooming, etc. So use layers, and keep layers turned off unless needed.
There are dozens of additional tips for keeping your model running smoothly, all of which will appear in future blog posts, such as painting with images instead of adding geometry, and using 2D components that “fake” the look of 3D objects. But sticking with the above advice on groups, components, layers, and hidden geometry, is a great start on your path to great modeling.