Can you help me reduce the number of polygons/triangles?


I’m still fairly new to Sketchup. I’ve created a model of a spiral staircase Staircase 2.skp (1.6 MB). The stats say it’s 280,000+ triangles. This will be part of a household interior that I’m building to import into Unity 5 for a game I’m developing.

Problem is, as it stands now when I walk around inside Unity the frame rate can drop to near zero. I’m assuming it’s because my model is too complex. How can I reduce the complexity of the model, yet maintain the basic look? I’d prefer to edit the stair component rather than having to recreate the model from scratch if possible.

Thanks for your time.

  • Ed.


Most of it is in the balusters. which you can see if you turn on the view hidden line option.

redesigning the balusters with fewer faces would obviously get the biggest gain in reduction.

Consider looking into using sub-components wherever possible… the bottom block of the balusters, the turning detail. etc…

You can probably get a pretty good reduction. but given the overall qty of the balusters things are going to add up quickly en masse.

MAYBE, look into the ‘Always Face Camera’ setting. . . If you could use that, you could really strip this down to a flat plane with some curved outlines. That would save a ton of edges and faces… But I’m not sure if gaming engines support this sort of thing.


I tried exporting as Collada and FBX. The Collada export is less file size, but a scene in Unity that had both versions in it seemed to run ok.

But, not when you’ve added colliders and try to climb the stairs! Perhaps you could do a much simpler model that has the colliders on it, but is hidden, and only show the detailed one, without it having colliders.


Here is a quick revision of the Banisters. See if that works better.
I reduced the polys somewhat.
Staircase 2.skp (1.2 MB)


That helps a lot, even with colliders on I can climb those stairs without losing frame rate.


Thanks everyone for the replies; it’s great to see so many helpful people.

Very nice Box! Can you give me a rundown of what you did so I can try it the next time I run into something like this? It looks like you reduced the number of sides to six, but I’m sure it’s more than that.


It was 8 sides and that’s almost all I did.
I took a profile through your banister with a section plane, then used Cleanup Contours, from Curvizard, this removed some of the segments in the curves of the profile, I could have simplified if further if necessary. Then I used an 8 sided circle to followme the shape and made it a component and did a Replace selected from the component browser.
I also remove a face that was causing Z-fighting, you’ll notice at the top of the stairs there is a face missing there. You could make that top component unique and put the face back just for that one.
One thing I didn’t do, which you should be aware of, is reverse the faces. You have made everything with the back faces facing out. When viewed in Monochrome you should only see white faces, but with yours everything is blue/grey, that is the default back face colour. It may not be a problem for you but many render engines and 3d printing software etc use the back and front faces to understand the geometry. Some renders ignore back faces so your textures would all fail to show. While in 3d printing the back face shows what is the inside and what is the outside of an object


When you imported into Unity, did you have to adjust the scale factor? I had to set the scale factor on the stairs to 0.025 to get the right proportion. When I do that and walk up and down the stairs with the FPS controller, the frame rate still bounces around. If I use a larger scale factor (like 0.1), the frame rate is much better, but the stairs are too big. Any idea why the scale factor would make such a difference? Is there a way to import the model into Unity and still have the scale factor around 1? Thanks.


The Collada and FBX models from your version both had to be scaled, 0.0254 for one, 0.01 for the other, based on whether it was from inches or centimeters. Box’s version happened to not need to be scaled, he probably used meters.

So, if you saw low frame rate on one that you had to scale, it was hopefully your original, and not the fixed one from Box.