Impact on File Size Due to the Use of PBR Materials in SketchUp 2025

[phippo]

A significant increase in SketchUp 2025 file sizes has been observed when using Physically Based Rendering (PBR) materials. To illustrate this effect, a test was conducted with a basic 3D model of a 2x2x2 unit cube, applying different types of materials:

• Cube with standard white color: 23 KB.
• Cube with a single PBR material: 3.2 MB.
• Cube with PBR material and background environment: 9.9 MB.

These results demonstrate that the inclusion of PBR materials, especially in combination with background environments, leads to a substantial increase in file size.

Implications:

In complex architectural models, which often require a wide variety of materials, the extensive use of PBR could result in considerably large file sizes. This raises concerns about:

• Software performance during the manipulation of large models.
• The time required to save and load files.
• The storage space needed for projects.
• The ease of sharing the files.

Recommendations:

It is suggested to conduct thorough testing and optimize the use of PBR materials in large-scale projects, in order to mitigate the impact on file size and ensure an efficient workflow.

[slbaumgartner]

Interesting observations! I’m not surprised by the impact from environment, as it involves an image and images can easily run to MB. The results for PBR seem to hint that they use images as well. Knowing that serious bloat can result is important, as there is a setting to convert all materials to PBR on load!

[ateliernab]

@slbaumgartner

it involves an image and images can easily run to MB

well yeah, I tried a 6k environment, 90mb. then a few 8k environments, 2-300mb
they are simply massive images.

edit : and that’s the price if you want hi quality environments. you’ll need beaucoup pixels.

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same for the pbr. the old default materials were 100px wide and a few kb. the new ones are in the 1000px ballpark, therefore more in the 1mb and more class.
add a normal map, ie. a second image, and the weight doubles. add an AO map and it triples.

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@phippo

Software performance during the manipulation of large models.

not really. you can always switch to a style with no materials, and the actual weight of the file has little impact on the performance. it’s mostly the quantity of geometry that does. and on that front, the new engines are really god, I have an old file that would run at 7-10fps and now runs at 30-50fps. same file, same version, different engine.

save and load might be slower with time indeed, except for people with good SSDs or hi-speed connexions (for trimble connect).
storage space can be an issue if you have a lightweight machine indeed, not an issue if you’re using trimble connect. plus external drives for long term storage are really cheap now.
same for sharing files, trimble connect is here. or free solutions like Smash, free up to 2gb.

the change of engine last year has an effect many don’t realise, users will need beefier machines, like other similar softwares.
the time where you could work on sketchup on a potato is in the past.

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digression

when I worked as a graphic designer, people were surprised to see how big my working photoshop files were.

I learned to work with as little degradation as possible. use extra layers, use masks, but don’t delete anything, you never know.
need to get rid of the surrounding ? mask. need to compose a scene ? layers and masks.

so off course, your 2k * 2kpx file is 200mb, it has a dozen layers. and when you flatten it is drops to 4mb.

[colin]

One thing about performance of large models, I did a test with a 100 MB file, that has a lot of PBR materials, and an environment. Deleting all of the materials and environments did reduce the file to under 13 MB, but the frames per second didn’t change. The full model set to Photoreal Materials had the same FPS as the version with no materials, set to Shaded With Textures.

The extra PBR maps seem not to cost any performance. They only let the GPU know more about the material. Of course, the 87 MB of materials in the model might take it beyond what a low end GPU can handle, but if you have a decent enough GPU, with more than the minimum amount of VRAM, it should perform well.

My test was on a 24 GB M4 Pro MacBook Pro. It is using integrated memory for the GPU, which often is not ideal. Even so, I was seeing 80 FPS with the 100 MB model.

[maxB]

It would be nice if you could edit / change the resolution of the default pbr textures. The non - diffuse can’t be viewed / edited. If you could, you could optimize the Rez. Maybe you want 1k for diffuse and just 512 for the pbr channels for some pbr effect. I do this all the time in unreal and it saves a lot of texture memory

[carretive]

In an existing file, ALL of my materials were converted to PBR. I’ve not gone into preferences and unchecked the necessary settings to avoid this in future. HOWEVER, in this one working file, how can I BULK uncheck Metalness & Roughness instead of going into each material one-by-one?

[eric-s]

Good points Colin. File Size and Performance (or lack thereof) are not necessarily equated. @phippo . This should not come as a surprise if

• A. You know that PBR materials and HDRI lighting environments are supposed to be this large as more data = better quality/more realistic render, and
• And B: if you recall that SketchUp has always embedded all data (ie geometry, images, textures, and now PBR Materials and Environments) into the host file and therefore the more data the larger the file. There is no reference manager like LayOut, where files can be externally sourced from.

@phippo

It is suggested to conduct thorough testing and optimize the use of PBR materials in large-scale projects, in order to mitigate the impact on file size and ensure an efficient workflow.

I don’t think that’s the answer. SketchUp’s default materials have been criticized for years for their low quality (but low file size!) and any reduction of data input will have a negative effect on the visual quality output.

If you’re serious about rendering in SketchUp, or concerned with large SU file sizes, than you should use a ‘traditional’ rendering extension, such as V-Ray - as V-Ray paths externally to large files, thus keeping the SU model small and light.

Example: A beautiful high poly Japanese Maple with all it’s high poly geometry and PBR material glory in SketchUp, is just 533kb…

…but whose source files add up to over 70mb. Big difference.