3d modeling

How to Use NURBS Curves in 3D Modeling: A Blender Tutorial

NURBS in Blender are the perfect primitive to use when you have a complicated subject in mind and prefer to flesh it out procedurally instead of sculpting or building it piece by piece. They are easy to use and very fun.

What is the best way to use NURBS curves? We have a few options that might interest you. Here’s how to get the ball rolling.

Create NURBS curves in Blender

NURBS curves are very similar to Bézier curves, but with a few differences. Although you can get close to a perfect circle with a Bezier object, you’ll never hit the nail on the head unless you use a NURBS curve instead.


Creating NURBS in Blender

To get started, jump into Blender. You have some NURBS options in object mode Add scrolling menu:

  • NURBS Curve and NURBS Circle under Curve.
  • NURBS Curve, NURBS Circle, NURBS surface, NURBS Cylinder, Sphere NURBSand Torus NURBS under Area.

Although both subsets are generated using the same principles, they actually behave very differently in the program: NURBS curves have only one interpolation axis per point, while NURBS surfaces use one. two, whichever one you choose. Essentially, a NURBS curve becomes a NURBS surface by definition whenever it is extended beyond itself.

Depending on whether you are using a NURBS curve or a surface object, your results may vary. You can use either as long as you know what you are looking for and how both work in the program.

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At this level, the most noticeable distinction will be the difference when you create surface geometry from a few NURBS objects. NURBS curves created in the Curves drop-down list will need to be simplified to a polygonal mesh before you can continue.

Working with NURBS in Blender

For each NURBS curve or surface you create, you will be presented with a series of control points that you can use to model the primitive. You never modify the curve or the surface itself – all the action happens through these control points.

To begin, select the NURBS object of your choice from the object mode menu. Add menu.


A NURBS curve in Blender.

The four default control points for a NURBS curve are relatively simple. Grab them like you would any other peak.


A NURBS surface in Blender.

For a NURBS surface, however, things get a bit more complicated. You have to deal with a matrix cage which may seem limited at first. If you subdivide the NURBS surface, however, you will see that with more geometry comes more freedom.

However, you cannot add individual vertices to this cage. Instead, you should do it by row or column, indicating where you want an extra degree of control.


Creating a flat NURBS surface in Blender.

A handy tip for flattening your NURBS surface: select each control point and use the Climb tool to scale everything z axis to zero while leaving everything else as is using the Adjust Last Operation panel in the lower left corner.


Besides the placement of each control point, you can also adjust them by Weight-the O field in the top Control Panel settings. This parameter pulls and pushes on the procession of points making up the curve, depending on their proximity to each weighted vertex, stacking and stretching accordingly.

Under Object data properties in the Properties panel, you can also compose your curve or surface Resolution settings. This will not affect the number of control points you have, however, it is simply used to increase or decrease the number of subdivisions breaking down the NURBS object itself.

What else can you do with NURBS in Blender? If you have a good idea and a plan, you can use them to do just about anything. There are several ways to proceed from this point:


  • You can grab any of your checkpoints with g and move them anywhere in 3D space; you can also Climb Where Turn the curve or any smaller part of it.
  • You can Subdivide the NURBS object by right-clicking it in edit mode.
  • You can Duplicate the NURBS curve to create a shape with several similar components.

Smoothing in 3D modeling can be used anytime you want to create a continuous shape from multiple disparate geometric elements, essentially tracing single geometry over all your hard and fast vertices and edges. More on that later.

If you created your NURBS objects using the Surface dropdown, you can use F fill in the space in between. If your NURBS object is from the Curve drop-down menu, you must first convert the NURBS object to a polygonal mesh.

How to convert NURBS to mesh in Blender

In order to create concrete geometry from separate NURBS curves, we first need to finalize the shape and convert it to a mesh. This method will work for any type of NURBS object in Blender.


Conversion from NURBS to mesh.

To convert NURBS to polygons in object mode, click in the Object scrolling menu. Under Convertselect Mesh. You will also find the same option when you right click on the object in your viewport.


Converting NURBS curves to mesh in Blender.

When you Tongue back in edit mode, you should see vertices dotting your NURBS curve at regular intervals. Now you can use this object like any other regular mesh in Blender.

Related: How to Merge Objects in Blender

Smoothing NURBS curves


Using NURBS curves to model a human ear.

One of the most obvious ways to use 3D NURBS curves in Blender is to use them as a base for modeling complex surfaces, like for the exterior body of a modern car or even for things like the branching of trees. . You lay out your design piece by piece, filling the gaps between them with a new NURBS surface.

If you chose NURBS surfaces or curves from the Surface drop-down list, you should be able to adjust your 3D smoothing without converting your NURBS objects to a mesh first. Otherwise, follow the instructions above and you’re free to work the same way with your new polygon geometry.


Using NURBS curves in Blender for 3D modeling.

Some other tips when lofting in Blender:

  • The rotation, position and relative pitch between all your NURBS elements will greatly influence your result.
  • Your new geometry may meet unexpectedly in the interspace unless you work carefully. If in doubt, you can always connect each part of your model one by one.
  • You will need to keep your NURBS resolution consistent between each leg of the loft to avoid strange artifacts or discrepancies between each NURBS object involved; it’s one of the trickiest parts, and it’s worth starting with a clean foundation.

One of the advantages of choosing a surface-derived NURBS object is that you are free to modify the underlying structure of the NURBS before finally committing the shape to a mesh. Anything that wrinkles, bends or mars the appearance of your NURBS surface can be easily dealt with without necessarily sinking.

Related: How to Use Reference Images in Blender

Turning NURBS curves

Much like in the world of physical woodworking and other types of industrial fabrication, you can rotate your NURBS shape and turn it into something like a vase, a Roman column, or anything symmetrical about an axis in orbit.


Create the world's ugliest vase with the screw modifier.

All you have to do is draw the base of your lath object in one of your perpendicular windows. Use the To screw modifier and adjust to your preference. You can also accomplish the same with the Turn tool in edit mode.


Lathing in Blender.

To hit To apply in the modifier drop-down list in object mode, and the transformation will be finalized. You can now work directly with this new polygonal mesh.

This is probably one of the most famous features associated with NURBS and Bezier curves in Blender. We strongly recommend that you give it a chance in any setting.


Related: The Essential Blender 3.0 Keyboard Shortcuts Cheat Sheet

NURBS curves are a 3D artist’s best friend

Once you get started with NURBS, you won’t be able to stop. Everything will be NURBS: funky and retro furniture, distant sci-fi designs, exquisite cutout patterns and much more are made possible with this incredibly versatile 3D modeling tool.


NURBS in Blender.
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