Many of the visuals we produce here in the Graitec Design and Vis department involve the use of mechanical models, whether this be for product visuals, animations or virtual reality.
When these models come to us direct from the customer they will have been modelled to a high degree of detail and accuracy in either Inventor, Sketch Up, or another 3D modelling programme. When we convert the models into files that we can use in Autodesk 3ds Max they will come in as highly detailed meshes.
As you can see from these images above, this model is made up of thousands of lines which split the model into sections. Each section is called a polygon. The higher the number of polygons in the scene the longer the scene will take to render – rendering is the process in which the computer takes all the information from the models, lights, cameras and environment we have set up in 3ds Max to produce our images or animations.
So, with more polygons there is more information for the computer to process. This is the reason we need to optimise these models, reducing the number of polygons to enable us to use them in visuals and animations. The same applies for VR; more polygons means a much slower running scene.
Below is a close-up of the feet from the model above. As you can see circled in red in the top left corner, this model contains over 135,000 polygons which is a huge amount for such a small, basic section of one model. To put this into perspective, we create a lot of visuals and animations for gyms here at Graitec, a typical 3dsmax scene of an entire gym including roughly 40 or 50 pieces of optimised gym kit will only be a few million polygons.
There are several different ways models can be optimised. The simplest and quickest way is by using the ‘ProOptimizer’ modifier. The problem with this is that it ruins the mesh, and the result is a model that was previously nicely quad modelled now a mess of lines (see right). This will produce sharp edges and faces that will be visible in the rendered images, particularly if the object has any reflective properties. We avoid using this method for this reason.
The process of optimising these models properly is very time consuming as we need to individually delete the lines you can see in the images in order to lower the number of polygons that make up the model. The lower the number of polys the better in terms of rendering time, but we need to be careful not to reduce the polys so much that we start to lose detail and see edges where there shouldn’t be.
This is the method we most often use when optimising, but occasionally, a model comes to us with so many polygons that it is actually quicker for us to re-model it from scratch rather than attempt to manually reduce the polygons. We can do this and keep the model perfectly accurate to the original by using the ‘draw on surface’ option in the Freeform modelling panel and picking the original model to build over.
Below are images of the same model after it was optimised. Instead of 135,00, this is now made up of only 7,000 polygons, and is ready to be used in a project.
Model optimisation is a service we provide for our customers in order to use their models in a project, and it is also a standalone service we can offer should you need mechanical models optimised for use in visuals, animations or virtual reality.
To find out more just click on the button below to request more information and a member of the team will be in touch.