How to speed up a slow SketchUp model
A SketchUp model lags when it has too much to draw: a few objects with tens of thousands of faces, shadows and profile edges turned on, and many copies stored as separate groups. Find the heavy objects first, then hide them with tags while you work, simplify or replace them, and turn off shadows until you need them.
Why SketchUp gets slow with a large model
Every time you orbit, SketchUp redraws every visible face and edge. Lag usually comes from a handful of objects, not the whole model: a detailed car, a tree, a sofa from the 3D Warehouse, a terrain mesh. One of those can hold more faces than the building around it.
Display settings multiply the cost. Shadows, fog, profile edges and some edge styles all add drawing work on every frame.
Find the objects with too many polygons
- Open Window › Model Info › Statistics and tick Show nested components. Note the total face count.
- Open the Outliner and look for imported items: furniture, plants, vehicles, fixtures and terrain are the usual suspects.
- Hide objects one by one (or by tag) and orbit. When orbiting gets smooth, you've found the culprit.
Watch for round things. A circle has 24 sides by default, and every sphere, bolt and cylinder built from it multiplies. Lower the segment count in Entity Info before you push/pull a circle if the detail won't be seen.
Display settings that cut the lag
- Shadows off while modelling (View › Shadows). Turn them on for the final views.
- Fog off (View › Fog) unless a scene needs it.
- Profiles and edge effects off. In the Styles panel, on the Edit tab's edge settings, untick Profiles and other extras such as extensions and jitter.
- X-ray and hidden geometry off when you don't need them.
Modelling habits that keep it fast
- Use components for repeats. Copies of a component share one definition. Copied groups each store their own geometry. See groups vs components.
- Put heavy items on their own tags (furniture, planting, entourage) and turn those tags off while you work. See organizing with tags.
- Use a light stand-in. Keep a simple box where a detailed object goes, and swap the detailed one in for the final views.
- Delete hidden leftovers. Hidden geometry still loads and saves.
- Keep the model near the origin. Content far from the origin (roughly 500 m or more) loses precision, which shows up as jitter and clipping.
Large textures mostly make the file heavier. If they slow orbiting too, leave Use maximum texture size off in Preferences › Graphics. Reducing file size covers them.
How Lookover finds the heavy parts
A Lookover review lists very heavy objects, hidden geometry still in the file, copies that should be components and deeply nested groups, with the objects named so Show me can take you to them. It also tells you when the model sits far from the origin.
Some have a one-click fix: identical components stored separately are pointed at one shared definition, and faces that could be one face (flat neighbours with the same paint) are merged. The AI part of the review looks for weight a rule misses, like hundreds of identical bolts modelled one by one, and says what each finding means for the model.
Lookover doesn't simplify meshes or swap in lighter objects for you. Those choices change how the model looks, so it points at them and leaves the decision to you.
Questions
How many polygons is too many in SketchUp?
There's no fixed number; it depends on your computer. A useful sign is a single object with over 10,000 faces in a model where it is only a small part of the scene. Those are the first to simplify or hide.
Does a faster graphics card fix SketchUp lag?
It helps with drawing, but a model with far too many faces stays slow on any machine. Cutting the geometry and turning off shadows usually helps more.
Does hiding objects make SketchUp faster?
It makes orbiting faster, because hidden things aren't drawn. It doesn't make the file smaller: hidden geometry still saves and loads.