Introduction to Maya: Polygons, NURBs and Sub-Ds

There are three main types of surfaces that you will come across in Maya. We take a look at what makes them differ from each other.


This week we'll spend some valuable time looking at the three different surface types that you will come across on a regular basis: polygons, NURBs and Sub-Ds.

Polygons: You will probably find that out of the three, you will predominantly use polygons. So what is so good about them? Well firstly, the tool set available to edit polygons is far wider than what is out there for the remaining two. The tool set makes it a breeze to model anything from an organic monkey to a hard-surfaced Chinook helicopter. The downside can be that if the resolution of your mesh is too low or if you have poor topology, then you may get artefacts such as pinching at render time, or deformation issues when rigging.

NURBs (Non Uniform Rational B-splines): These, on the other hand, are fantastic for creating smooth, curved surfaces, such as a car bonnet. They are mathematical in their creation and their tessellation at render time creates super smooth results. The major downside for me is that the toolkit is limited and if you are trying to model, say, a humanoid character, you will need to use many, many NURBs patches, as you will not be able to get the desired results from a single surface.

Sub-Ds: These can be considered a combination of polygons and NURBs: you get to use the polgyon modeling toolkit whilst also having a surface that will render very smoothly. A further advantage is getting to add localized detail easily by subdividing specific areas. Because getting the hang of polygons and NURBs will enable you to use Sub-Ds, they're not included in the following steps. Your choice of what to use is going to come down to what is best for what job and also what your preference as a user is. Try them all to see what suits you.


Step 1: Creating Polygons

You can find the default polygon objects by going Create > Polygon Primitive and picking from the selection - I'm going for the humble cube. But, before you create a primitive, scroll down to the bottom of the dropdown menu and uncheck Interactive Creation. This allows you to draw the polygon object anywhere in the viewport.I heap scorn upon this, however, as I like my primitives to be created in the center of the world space.

You can also create your poly object by holding the Shift + RMB. This will bring up a marking menu and dropping the cursor over your chosen object will drop it into the viewport. Another method is to simply type "polyCube" into the command line.

Creating a polyCube using the main menu, a marking menu and the command line

Creating a polyCube using the main menu, a marking menu and the command line

Step 2: Editing Objects

Currently, we can only edit the shape as a whole with the Move, Rotate and Scale tool. If we want to edit a certain vertex or a selection of edges or faces, we will need to go into sub-component mode.

Place your cursor over the cube and hold down the RMB. You should see the words Vertex, Edges, Face and Object, as well as a few others on the marking menu. You can also hit F9, F10 and F11, with F8 taking you back to object mode.

Select any of these and you will be able to start pushing and pulling the points around. This allows us to edit the current level of detail that we have. Now if you want to add extra detail, keep on reading.

Editing the geometry on a sub-component level allows you to make localised changes as opposed to global changes

Editing the geometry on a sub-component level allows you to make localised changes as opposed to global changes

Step 3: Mesh Tools

To edit polygons, we will use the Edit Mesh and Mesh toolset. To switch to the Polygons sub-menu, either edit the dropdown menu on the Status Bar to Polygons or hit F3 on the keyboard.

You should now find the Mesh and Edit Mesh tools available. The Mesh tools allow you to make more global changes, such as combining different polygonal objects, or separating parts of an object.

The Boolean tools, which can be dangerous in the wrong hands by the way, are also found here as well as the very fantastic Sculpt Geometry Tool. You can think of the Sculpt Geometry tool as a simplified Mudbox or ZBrush, allowing you to push and pull points. In my opinion, it still achieves the best results for relaxing a surface than any other package I have used.

Using the Boolean tools and the Sculpt Geometry tool

Using the Boolean tools and the Sculpt Geometry tool

Step 4: Edit Mesh Tools

So these are going to be the meat and potatoes of your modeling toolkit unless you are using Maya 2014, where the Advanced Modelling Toolkit will come into play.With these tools, you can begin pulling selected edges and faces out using the Extrude tool, add extra detail using the Insert Edge Loop tool and cut into a model using the Split Poly tool.

To be honest, there is a huge toolset there, but I tend to mainly rely on the afore-mentioned tools as well as the Merge Vertex tool. Generally, these tools can be found in most 3D applications so you should be able to easily transfer your skills from Maya to another package.

You can access some of these tools by having an object selected and holding Shift + RMB, which brings up a marking menu. I like to use this marking menu as it has the original Split Polygon tool, which I prefer over the Interactive Split tool available in the Menu bar. Grab a simple cube and have a play; experiment and get to know your toolkit.

The meat and potatoes of your modelling toolkit

The meat and potatoes of your modelling toolkit

Step 5: Editing NURBs Surfaces

To edit NURBs objects, you will need to switch to the Surfaces module by using the dropdown menu in the Status Bar or hitting F4. Then go Create > NURBS Primitives and select any object from the list. Holding the RMB will again allow you to edit the object's sub-components.

Instead of Vertex, Edges and Faces, we now have Control Vertex, Hull, Isoparm and Surface Point as well as a few others. Popping up to the MenubBar, you now have access to the Surfaces and Edit NURBs tools.

There is a slightly different methodology when using these tools compared to the Edit Mesh tool, so take some time to experiment with them and again, try and take note of the tools that will be of most use for the future.

Editing a NURBs surface

Editing a NURBs surface

Top Tip 1: Converting Objects

Sometimes it's easier to model using one of the three surface types, as the task will be quicker to perform.

For example, go to Create > CV Curve Tool and create the profile of half a glass in the front viewport. With the curve selected, go Surfaces > Revolve and we should get a NURBs object that looks something like a glass.

This type of action may have saved us a couple minutes in time, but now let's just say that every other model within our scene has been created from polygons and in the interest of consistency, we also want this asset to be a polygon. To do this, select the newly created NURBs object and go to Modify > Convert > NURBs to Polygons (Options). Now set the Tessellation Method to Control Points and hit Apply.

Taking a curve, using the Revolve tool to make a glass and then converting the NURBs surface into a polygon

Taking a curve, using the Revolve tool to make a glass and then converting the NURBs surface into a polygon

Click HERE to see the previous tutorial in this series.

Want to start from the beginning? Click HERE to see the first tutorial in this series.

To see more by Jahirul Amin, check out Beginner's Guide to Character Creation in Maya
and 3ds Max Projects

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