Showing posts with label curves. Show all posts
Showing posts with label curves. Show all posts

Thursday, October 6, 2016

Read How to use Bezier Curves in Blender Now


An edited curve

What are curves within Blender?

Curves within blender are normally used to create the outline of an object or trace over something e.g. a picture. It is similar to the pen tool in Photoshop as to how it works and what it’s used for. There are two types of Curves, Bezier and Circle.

How to use the Curve tool

In this tutorial I will be drawing a Batman logo to show you how to use the Bezier Curve.

Step One:When you are ready to add your curve in to the stage, go into Orthographic view (numpad 5) and top down view (numpad 7) and delete the default box by right clicking it and pressing x then clicking delete. Then press shift+A> Curves>Bezier Curve and you will see the following:


newly added curve

This is your curve. It cannot be edited or re-shaped until you go into edit mode by pressing TAB. Once there you should see this:

handles on curve

The layout the curve is in can look quite complicated and the arrows tend to throw people off. If you’d prefer to turn them off press N then in the new menu that appears, under “Curve display” un-tick normal as shown below and the arrows will disappear.

getting rid of normal

Step Two: To change the shape of the curves you use the handles which are the red straight lines coming from the points. The points between the two red handles, on the curved line are where the curve's control points are. These points can be moved to change where the curve actually is. The red lines can be adjusted in length and position. The length changes how big the curve is and the position changes the direction. Play around with the handles a bit to get used to them.

adjusting the handles

Step Three:If you practised step two you will notice that when you change the position of one handle, the other handle stays in line with the one you changed. This is because of the handle type. To change this press V and click on vector and you will notice the handles go green and can be adjusted freely.

vector handles

The vector handles are necessary to create shapes where the curves on either side of a point go in different directions e.g. the Batman logo wings as seen below. To add a new point, right click the point you want it added on to, and press E (for extrude). You will then notice you are dragging a new point. Place it in a suitable location and adjust it how you want.

adding a new point

Continue this process until you have the shape you want. If the shape you want to make is symmetrical, you only need to draw up half of the shape. To see the shape without handles, go back into object mode using TAB. To continue editing, press TAB again.

how to see your shape

Step Four:If the shape your drawing with your curves is symmetrical then you will need to duplicate it, then mirror it. To do this get out of edit mode into object mode, press Shift+D then enter and then press CTRL+M+X then enter. Reposition it if it is off.

mirroring your shape

This has given us two different Bezier curves which can’t be edited at the same time. To change this go into object mode, right click one so it is highlighted as above, then Shift right click the other and press Shift+J to join them. You can then TAB back into edit mode. Here you can right click one point, then shift right click the corresponding one on the mirror side, and press F to connect them (stands for fill).This is how I connected the head above and the tail below.

finished shape

When you connect the two points at the bottom for the tail, you need to add a new point in the middle to drag down. To do this click subdivide in the left toolbar after you connect them by pressing F, as shown below:

subdividing your curve line

Step Five:We now have the outline of our shape finished but now we can make it more detailed, or turn it into a rendered image. This last step is not necessary, but it is good practice and turns the curve into a nice image.To begin this process we have to click the curves tab in the right toolbar and change it to 2D to fill the shape in. make sure you have the curve selected to get the curve tab to show. you can also change the resolution to 24 to give it more definition.

making your curve solid

You can then go to the top of the stage to where it says blender render and change it to cycles render. After that, click the world tab (you must have nothing selected. Press A while over the stage to deselect if you have anything selected) in the right toolbar to get the menu below displayed.

making your curve an image

changing colour of background

In this menu go to surface and change the colour to what you want the background of the image to look like. I chose black.

You can then right click the curve and click the material tab in the same area where the world tab was. Add a material by clicking the add material button then go down to surface. change the surface to emission, then pick the colour you want to use.


changing colour of curve

Finally, position your view of the image to wherever you want the camera to be. I recommend using a top down view (numpad 7). You then press CTRL+ALT+Numpad 0 to set the cameras location. You can press numpad 0 again to exit out of the camera view. Right click the camera then click the camcorder tab in the same place where the world and material tabs were. Change to Orthographic and use the Focal Length and the Shift options shown below to reposition the camera. To view these changes press numpad 0 over the stage again to show the view. It will update to the changes you make in real time.

taking a picture

Once you’re happy with the position of the camera and the other settings you have made, click the camera tab and then click render, or just hover over the stage and press F12 to take a rendered image of your curve. As you can see below, I have a fully finished rendered image of my custom made batman logo.

Bezier Curve Batman Logo in Blender
final image

Friday, January 29, 2016

Curves in Blender

Wine Glass made from Curves in Blender
Wine Glass made from Curves in Blender
In Blender there are 2 types of curve. The name of these 2 curves are Bezier and NURBS (Non-Uniform Rational B-Spline) Curves. These two curves can be used to create 2-D and 3-D objects with complex curves such as cars, bottles and many other things.

Bezier Curves have no tangent and are connected to the line. NURBS do not have tangents and their curve control points are not connected to the line. When choosing between the two it is best to go for the one you feel most comfortable using, although Bezier Curves are considered easier to control due to the control points being on either side of the line, while NURBS Curves are easier for the computer to calculate efficiently.


Bezier Curve
NURBS Curve

Curves are used to model the outline of a shape or object. Curves can be 2-D or 3-D. 3-D curves can be mapped to anywhere in the 3-D space but 2-D curves are restricted to staying in the X and Y plane. Curves are 2-D by default when you bring them into a scene.

Bezier Curve

To get a Bezier Curve press ('Shift' + 'A'), select curve then Bezier Curve. It helps to press ('7') on number pad to get a better view. Pressing ('Tab') gives brings you into Edit Mode. Once pressed you will see a Black line with two pink lines on either side and other smaller black lines that look like legs coming off the larger black line. At each end of the pink lines there are 2 orange dots, these are control points and are used to alter the curve of the line.

Bezier Curve in Edit Mode
The position and length of the pink lines can be manipulated by right clicking any of the control points. Changing the position alters the direction of the curve while changing length alters the curve of the line.

NURBS Curve

To get a NURBS Curve press ('Shift' + 'A'), select the curve option and then choose NURBS Curve. Next it helps to go into a top-down view by pressing ('7') on the number pad as it gives you a better view of the curve. Press ('Tab') to bring the curve into edit mode. This should show something similar to the Bezier Curve except instead of two pink lines there is one yellow line broken into 3 segments. On the yellow line are 4 orange control points that allow you to manipulate the curve to the shape you require.
NURBS Curve in Edit Mode

Moving the orange control points on the X-Axis increase the length of the curve while moving it in the Y-Axis changes the bend in the curve. This is similar to the Bezier Curve.


*To turn of the lines that look like legs on your curve press 'N' then un-tick the box that says Normal underneath Curve Display.*


Properties of Curves

The properties of curves can be altered in the side panel to suit your preferences. Everything from    2-D to 3-D, resolution, twisting, path/curve deform and fill can be adjusted in this panel.

Curve Properties Panel

2-D and 3-D Curves

When you bring a new curve into a scene it automatically comes into the scene in 2-D. This can be changed so that curves are 3-D when they are brought into a scene. To do this just switch press either the 2D or 3D button in panel under curves.

2D or 3D Curve Option

Scaling Curves

Curves can be made bigger by selecting the curve and pressing 'S' on the keyboard. The curve can -now be made bigger by moving the mouse, once you left-click the screen the curve will stay the size that you left it.

Scaled Bezier Curve

Hotkeys for Curves

New Curve: For a new curve press 'Shift' + 'A' and under the curve option select the curve type you want.

Enter Edit Mode: Press the 'Tab' button to enter Edit mode.

Top-Down View: Press number '7' on the number pad to go into top-down view giving you a better view of the curve.

Subdivide a Curve: Select two parts of a curve segment and press 'W' to divide the curve into two new segments.

Join Separate Curves: Highlight the curves and press 'CTRL' + 'J'.

Fill: To fill a closed curve press 'Ctrl' + 'J'.

Tilt a Curve: To tilt a curve select an endpoint and press 'CTRL' + 'T' and move the mouse.

Convert Curve to Mesh: To convert a curve to a mesh press 'ALT' + 'C'.

Extrude a line: To extrude a line select the point you want to extrude from and press 'E'.

How to Make a 3-D Wine Glass using Bezier Curves

First open a new Blender file and delete the starting cube. Next press numbers '5' and '7' on the number pad to go into a top-down orthographic view. This will give you a better perspective of things in the scene.

Top Orthographic View

Next press 'Shift' + 'A' then select Curve, then select Bezier Curve. This will add the Bezier Curve to the scene. You can change the resolution of the curve if you wish underneath the Curve Panel. This technique can be used for many similar objects but for the purpose of this tutorial I decided on doing a wine glass as it is simple and easy to do.

Outline of Glass

Next in order to get the 360 degree object that you are looking for you will want to go to the right hand panel and click on the modifiers panel. Click add 'Add Modifier' and add a 'Screw Modifier'. Under Apply switch the Axis to the X-Axis.

Add Screw Modifier
Move the different parts of your object around until you are happy with its appearance. This is what my wine glass ended up looking like.

Finished Glass





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