BLENDER - Curve Modifier with Geometry Nodes (English)

Name: BLENDER - Curve Modifier with Geometry Nodes (English)
Uploaded: 2025-05-05T11:33:27+00:00
Duration: 15 min 15 s
Channel: JPFR1906 🇦🇷 (TV, Radio y muchos más)
Description: BLENDER - Curve Modifier with Geometry Nodes (English)<br /><br />Special Thanks for ErinDoes and Blender Bash who tought me how to do it.

JPFR1906 🇦🇷 (TV, Radio y muchos más)

5/5/2025

BLENDER - Curve Modifier with Geometry Nodes (English)

Special Thanks for ErinDoes and Blender Bash who tought me how to do it.

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00:00Blender Operations Notebook number one. Curve Deform Modifier using Geometry Nodes.

00:07Curve Deform Modifier the traditional way. Let's demonstrate how to apply a Curve Deform

00:16Modifier to an object. Here, I increased the cube size along the y-axis by 20 units.

00:23I entered edit mode and made 20 cuts along the y-axis.

00:26Then I added a Bezier Curve, which will be used to deform the object. I scaled and edited this curve.

00:46I selected the object, went to the Modifiers menu, and added a Curve Deform Modifier.

00:52I selected our Bezier Curve as the Curve object. In this tutorial, we will use the y-axis for

01:00deformation. Done. Now the object will be deformed according to the shape of the curve along the y-axis.

01:11Now, let's show how to create this modifier using Geometry Nodes.

01:14In Geometry Nodes, there isn't a native node for this purpose, so we'll need to build it manually,

01:21and here we'll explain how.

01:22We'll need an object, in this case a cube that will be deformed, and a curve. Each point on the curve has a

01:38normal vector, in red, and a tangent vector, in green, both of which can be read directly. However,

01:48we'll need a third vector, calculated from the two previously mentioned ones, using a mathematical

01:53operation called cross product. Besides these vectors, we'll also need the position of each point

02:00along the curve. Geometry Nodes already has a node called sample, which directly reads position,

02:07normal, and tangent vectors of each point on the curve. The other required vector is perpendicular

02:13to the normal and tangent vectors, and is calculated using the cross product.

02:17The cross product vector is perpendicular to the plane formed by the normal and tangent vectors,

02:34shown in blue in the video. But how do we calculate this vector?

02:51No need to do it manually. Blender calculates it for you.

03:05Here we have a parallelopiped that will be deformed to match this curve.

03:14Each point of the parallelopiped along the y-axis corresponds to a proportional position along the curve.

03:21Each point along y will be positioned along the curve, considering the direction of the normal

03:33and cross product vectors at that point. To do this we'll map the x value of each object vertex

03:40to the normal vector of the corresponding curve point. The z value of each vertex to the cross product

03:46of that point. The y value will be mapped to the curve point's position.

03:52Let's see how this is calculated. We'll take one vertex as an example. This vertex has x, y, and z values

03:58in space. Its x value is multiplied by the curve's normal vector at a specific point. The result is

04:04added to the z value multiplied by the cross product. Then, this result is added to the curve point's

04:10position vector, corresponding to the vertex's y value. Each curve position is mapped to the parallelopiped's y-axis

04:16position, since in our example we're using this axis for deformation. Now let's demonstrate this with

04:22an example. Let's take this vertex with index 0 and position x equals 4, y equals 0, z equals negative 4.

04:30We'll multiply x equals 4 and z equals negative 4 by the curve's normal and cross product vectors

04:36at the corresponding point. At this stage we'll ignore the position vector.

04:43So we get these results, which we add together, producing the final result, the new position for this vertex.

04:54Now let's repeat this for the other vertices.

05:07You'll see that the object is aligned with the normal vector of the curve at each point.

05:16Now let's add the curve's position component to the calculation.

05:19Done. This section of the parallelpiped is now deformed and positioned according to the curve.

05:23Now we repeat for the rest. The next object section, further along the y-axis,

05:26will be repositioned according to the curve, and so on until the last vertex.

05:40Note, the object's size along the deformation axis must be normalized to 1. That is, regardless of

05:46its actual length along this axis, in this example it's 30 units along y, it must be scaled from 0 to 1

05:52for deformation purposes. How do we do this? Let's look at an example with a more complex object.

06:04There's a node called bounding box that reads the min and max vertex positions of an object.

06:15The bounding box encloses the object in a virtual box.

06:23Its size adapts to the object's dimensions, so it always knows where the edges are.

06:32Now, to normalize or compress this size into a range from 0 to 1, we use the map range node.

06:39Switch the map range mode to vector.

06:45In its vector input, connect a position node that reads each vertex's position.

06:50Then, connect the min and max outputs from the bounding box to the from min and from max inputs of map range.

07:03This way, all vertex positions will be remapped to a 0 to 1 range.

07:07Now that we have the tools, sample curve, cross product, bounding box, and map range,

07:20let's build the curve to form modifier.

07:31Enables wireframe view to better see the mesh edges.

07:36Enable geometry nodes workspace.

07:39With the cube selected, create a new geometry nodes node tree.

07:42We'll create a parallelepiped using a cylinder with 4 vertices.

07:55Set depth to 20 and side segments to 50.

07:58Add a transform modifier to rotate 90 degrees on x-axis and 45 degrees on y-axis.

08:16Use join geometry to connect the object to the group output.

08:20Now add a curve.

08:20We'll use a spiral in this example.

08:25Connect the curve's output to join geometry.

08:27Now insert the necessary nodes to normalize object size as explained earlier.

08:40Add a bounding box node and connect the object to it.

08:42Add a map range set to vector mode.

08:51Connect bounding boxes min to map range's from min and max to from max.

08:59Add a position node and connect it to map range's vector input.

09:07Add a sample curve and connect the curve to its curves input.

09:12Add a set position node on the object line.

09:27On the object line before join geometry, add a set position node.

09:31This will reposition the vertices.

09:40Add a separate x, y, z from the map range output.

09:50And connect its y output to the factor input of sample curve.

09:54This will associate object vertex y positions with the curve's points.

09:58Now we'll set up the vector math.

10:07Add two vector math, add nodes, and chain them.

10:10Add a cross product node to compute the perpendicular vector.

10:22Add a cross product node to compute the perpendicular vector.

10:35Add a cross product node to compute the perpendicular vector.

10:39Connect the tangent and normal outputs from sample curve.

10:44Connect the position output of sample curve to one add node.

10:51Add two scale nodes, vector math set to scale.

10:54Connect cross product to one scale and normal to the other.

11:07Connect each scale to the remaining add nodes.

11:13Connect each scale to the remaining add nodes.

11:24Now we need to get x and z values from the object's vertex positions.

11:28Add a position node followed by a separate x, y, z.

11:36Connect x to the scale with the normal vector.

11:47Connect z to the scale with the cross product.

11:49Now that the math is done, connect the final result to set position.

11:58Voila!

11:59Your object is now deformed into the shape of the spiral curve.

12:03Adjusting the to min and to max values in map range will change the deformations

12:08start and end points.

12:09You can add math nodes to smooth these changes.

12:19Imagine just type!

12:20You can add math to the curve as the wave.

12:21But� will change the whole round line,

12:24and there will happen the leakage.

12:26Now 최대 1 and 3.

12:29If you will Sóce for the loop forramer short curve.

12:32The97 you octagon can win the allса!

12:34Loveā is just a dream set of evolve.

12:37It may be painful as anän if you want to Ke programa!

12:41Just a dream set of dream set of loss.

12:44Loveā is just a dream set of events!

12:45Starting with Blender 4.2, there's a Set Curve Normal node that allows you to change the curve's normal orientation.

12:58If you set it to zit up, the normals point towards zit, preventing twisting.

13:09In this example, we use the Y-axis for deformation, but other axes are also possible.

13:14For example, along the X-axis.

13:18To do this, instead of connecting the Y-value extracted from the map range to the factor input of the sample curve node,

13:27we're going to connect the X-value instead.

13:29And instead of multiplying the X-value by the curve's normal vector, we'll multiply it by the Y-value.

13:35And finally, we'll input values on the X-axis in the to-min and to-max fields of the map range,

13:43instead of using the Y-axis.

13:47Final tips. Here we have an object that will be deformed along a closed curve.

13:51In other words, a cyclic path.

13:53First, let's check whether the object's normal vectors are facing the correct direction.

13:58Go to the Overlays menu and enable the Face Orientation checkbox.

14:03If the object appears red, as shown here, the normals are pointing the wrong way.

14:08To fix this, go to the connection between the curve's normal and tangent vectors used in the cross-product operator and reverse the connections.

14:15Done. If the object appears blue, its normals are now pointing correctly.

14:19Here we can see that when the object reaches the end of the curve, even though it's closed and cyclic, it collapses.

14:26The same happens when it reaches the beginning.

14:29For a smooth cyclic movement without collapsing, we need to add a set spline cyclic operator after the curve and check the cyclic box.

14:39Then, in the line connecting the deformation axis to the factor input of the sample curve, we should insert a math operator of type modulo.

14:59Here, we use the florid modulo.

15:01The modulo value should be set to 1 since the factor ranges from 0 to 1.

15:06Done.

15:08With this, we have a smooth cyclic deformation.

15:12You

BLENDER - Curve Modifier with Geometry Nodes (English)

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