Why your SketchUp file is so big, and how to shrink it
A SketchUp file is usually big because of large texture images, imported objects with far more faces than they need, and groups copied many times instead of placed as one component. Start with Window › Model Info › Statistics › Purge Unused, then shrink textures and turn repeated groups into components.
Why is my SketchUp file so big?
A .skp file stores every face and edge, plus a full copy of every image used as a texture or placed in the model. The things that add the most, roughly in order:
- Textures. A 4,000-pixel photo on a wall is stored in full, even if the wall is a few pixels wide on screen. On many models, textures are most of the file.
- Heavy imported objects. Furniture, plants and cars from the 3D Warehouse or other sources can each carry tens of thousands of faces.
- Copied groups. Every copy of a group stores its geometry again. A component stores it once, however many times you place it.
- Unused items. Materials, components and styles you tried and stopped using stay in the file until you purge them.
- Hidden geometry. Hiding something doesn't remove it. It still saves with the file.
Purge unused items
Open Window › Model Info, choose Statistics and click Purge Unused. SketchUp removes components, materials, tags and styles that nothing in the model refers to. Save the file afterwards to see the new size.
You can also clear one kind at a time: the Materials, Components and Styles panels each have Purge Unused in the details menu of their In Model collection. Or delete items one at a time there, if you only want to clear some of them.
Purge only removes what nothing uses. A component placed once, deep in a group, is still in use. So is a material on a single hidden face.
Shrink textures
Open the Materials panel and look at In Model. For each textured material, check how big its image is. Few textures need more than 2,048 pixels on the long edge for on-screen work or renders at normal distance.
To shrink one, edit the image in an image editor at a smaller size, then load the smaller file into the same material so every face keeps its paint. Placed images (photos imported as images rather than textures) are stored in full too. If you only need the picture on a surface, a texture on a face is easier to resize and reuse.
Cut down the geometry
- Replace copied groups with components. Select one group, right-click and choose Make Component, then swap the copies for instances of it. See groups vs components.
- Simplify or replace heavy objects. A lighter model of the same chair often looks the same in a view. Statistics with Show nested components ticked helps you see where the faces are.
- Delete hidden geometry you don't need. Turn on View › Hidden Geometry and delete what is there for no reason.
- Erase stray edges. They don't weigh much each, but leftover linework adds up. See stray edges.
A smaller model also tends to be a faster one. Speeding up a slow model covers the overlap.
How Lookover helps
A Lookover review lists what makes the file heavy and fixes the parts with a clear answer:
- Materials, tags and components nothing uses: one-click fixes.
- Duplicate materials (the same plain colour twice): one click repaints with one material and removes the duplicates.
- Identical components stored separately: one click points the copies at one shared definition. Each copy keeps its position, size and paint.
- Textures over 2,048 px, placed images, hidden geometry, very heavy objects and copies that should be components: listed with examples, for you to decide.
- Styles no scene uses: listed only. SketchUp can't undo removing a style, so Lookover doesn't do it for you.
The AI part of the review also looks for weight that a rule misses, such as hundreds of identical bolts modelled one by one. Every fix is one undo step.
Questions
Does Purge Unused delete anything I'm using?
No. It only removes items nothing in the model refers to. Save a copy first anyway if you keep spare materials or components in the file on purpose.
Why didn't purging make my file much smaller?
Because the weight is usually in what you are using: large textures and heavy objects. Purge clears the leftovers. Shrinking textures and swapping copied groups for components usually saves more.
Do components really make the file smaller?
Yes, when the same object appears more than once. Each copy of a group stores its own geometry, while every instance of a component shares one definition. Twenty chairs copied as groups store twenty chairs; as one component they store one.