Tips on optimising existing 3d models to save on computational resources?


Hi there,

I’m still fairly new to Rhino, and have been using it recently to model the general arrangement of a high-speed catamaran ferry (I’m a student Naval Architect).

I’ve currently got some step files that I’m using for a heap of chairs in my model. The problem is that the step file I’ve been given seems to be pretty intricate, and hence my computer seems to be struggling to deal with the model fluently (even when only in wireframe). Not to mention this is with only 1x cluster of chairs, when eventually I’ll be hoping to have around 100 of the same set of chairs throughout the model.

Is there an easy way to tidy up or simplify the step file without pulling it apart piece by piece? by either using Rhino or through other means?

I have attached the step file for your perusal, if it helps.

Thanks in advance for your help,


PC Specs:
CPU: i7 7700k
GPU: Nvidia GTX 970
HD: 2x 256GB SSD

Sea-Force 450 HB All Arms 3s Worx.rar (4.5 MB)


A workflow I’ve used is the following (when dealing with repetitive complex geometry) is a combination of using blocks, meshes and worksessions.
You can mesh the model with low settings, and join. This immediately will speed things up- but, you don’t have editable geometry as a trade off so keep a copy of the original obviously.
I recommend keeping some curves at the bottom of the model as reference points to move the model around (to snap to etc, rather than turning on snap to vertices that slows things down I think).
You can then either ‘reducemesh’ by a percentage you like to get a model that looks acceptable but is light.
Then, run the ‘block’ command, and turn your mesh into a block. Read a little on how blocks work if you need.
Then, copy and paste around as much as you need- with a low res mesh, you should be able to get a high number of objects in your model.
Finally, if you REALLY needed to, you could edit your block, paste back in either a higher mesh resolution version or the original step for some sort of final output/rendering or something. This would slow the model down yes, but you could switch out the block again for a low res when not needed.

Another option is to have the furniture separated out into another file, and then using the worksession command to bring a visual version of it into your file that you can turn on and off as needed.
You can split up your models into many smaller files of geometry classes this way if you like. Look into worksessions if you haven’t used them before.


I forgot to ad… as a final resort if you have meshed everything and reduced the mesh to an acceptable visual level, you can join all the objects together as one big mesh. Rhino likes this very much, and will speed up noticeable. The problem being you will not be able to use blocks for this method, and editing/changing the layout and the chair is then a bit of a hassle. Trade offs.


Thanks very much for that! I’ll give it all a crack and get back to you with the results.