How to disable Image Grids in Carrara

You know those grids in Carrara that often get in the way? Those that only appear in the viewport and not in the final render. The ones that show you the outlines of your objects in yellow:

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Sometimes you can’t see your scene with too much clutter. And I keep forgetting that there’s a super easy way to switch these grids off.

Cast your eye to the to of the viewport and find the following icons:

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See those three little grid icons? Click any of them to make it disappear in the viewport. It’s that easy! Disabled grids turn dark, enabled ones are lighter in colour:

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With the side grids switched off, the scene looks less cluttered.

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Sometimes I forget how user-friendly Carrara can be ūüėČ

How to reload image textures in Blender

We often have to tweak images in an external application¬†while they’re already applied to a 3D object. To see our changes in action, it is necessary to reload the textures in Blender. Few applications detect such changes automatically (which is sad – because it’s not exactly rocket science to implement this).

To do this, change to the UV Editor in Blender and select Image – Reload Image.

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You can also use the keyboard shortcut ALT+R without changing into the UV Editor.

How to use reference images in Blender

Reference images are helpful for modelling objects or to add simple backgrounds to scenes. There are at least two ways in which we can add them in Blender.

 

Adding Background Images

One way to do it is via Background Images. On the tab next to the Properties Palette (expand it with the little plus icon on the top left), find the Background Images tick box.

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Open an image of your choice and select¬†the relevant changes, such as opacity, stretch/fit/crop, and select which axis you’d like this image to appear on. Blender does not allow you to select more than one image at a time, so you can’t add all views of an object. But as you load more images, Blender does remember them in the image list, so you can pick a new one from there instead of loading it again.

Note that such images will only show up in orthogonal views, not in perspective views. To change your current view, select View – View Persp/Ortho.

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Loading images as planes

Another option is to import an image directly as a plane. It’s a shortcut of creating a fully UV-mapped object into your scene and position it just the way you like it, preserving the aspect ratio of your image. This is an add-on that’s installed by default with Blender, but it needs to be activated to be used.

Under File – User Preferences, head over to the Add-Ons tab. Select the Import-Export section and find Import Images as Planes. Tick the box to the right of this option and it’s activated.

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Now head over to File – Import and select Images as Planes. Pick an image and you’ll see a new plane object in your scene.

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View your scene in Textured, Material or Rendered modes to see your image.

How to use Blender as a simple Render Farm for animations

Blender has a bafflingly simply way to let several computers render the same animation.¬†Render Farms are usually setup in a way that one machine is the “master”, and the others are declared “render slaves” that each render a single frame or even a single bucket of a frame. The master then assembles everything into a single video file.

But rendering directly to a video file isn’t always desirable because single frames cannot easily be re-rendered if there was a problem. While there is a way to setup Blender using such a master/slave setup, there is a much easier way to render an image sequence: all we need are several computers that can see the same directory on the network. This could be a Dropbox folder, so the render nodes don’t even have to be on the same network.

Here’s how to let several computers render the same animation together, producing a directory full of images that can be assembled in a video editor.

Create your animation and head over to the Render Settings property. At the bottom of the screen, deselect Overwrite and select Placeholders. For the Output Path, navigate to your shared folder than can be seen by all networked computers.

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Under Render, hit Animation to start rendering the image sequence. Do this on every computer on the network after loading the same animation file. Blender will go to work on all nodes, each of which will render the next frame in the sequence.

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Minor Caveat

The way this works is that each node looks at the folder and takes a look at what files are already there, then it picks the next one and renders it. Because there is no communication between the nodes you may experience occasional frames that have been rendered twice – because two nodes may see that 23 frames have been rendered and the 24th one would need to be picked next.

Such double-renders are marked in the sequence though, so it’s easy to delete them before assembling the sequence. The more computers are involved, the more this is prone to happen. In my tests I’d say that of a 100 frame animation there are perhaps 10 additional renders. Blender marks them as “conflicted copy” with the same image and the computer that caused them.

In my opinion this is a very small price to pay given the fact that you do not have to deal with complete re-renders or network communication trouble. This way of rendering can even utilise remote machines without nothing more than a simple shared folder.

Grouping and Parenting in Blender

Blender is different than other applications. If you’ve used grouping or parenting in other applications, it may throw you off guard how Blender thinks about those things. A little explanation is in order to bring clarity to our cluttered 3D minds.

Usually we can group objects together so that when we select one, the other one is selected at the same time. In other applications, grouping and parenting are the same thing, but not in Blender. Groups are in itself only of limited use, while parenting is what other apps call grouping (from what I understand).

 

Grouping

To group several objects together, select them all by holding SHIFT and right-clicking each object, then select Object – Group – Create New Group.

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On the right hand side you can name your new group. Note that if you miss this opportunity, there doesn’t seem a way to do this later: I haven’t managed to find a way to even display groups in the current scene.

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The outline of all your selected objects will turn green, and any transform action will affect all selected objects at the same time.

In the scene hierarchy however, neither the group is displayed, nor are any of your objects parented. In fact, the group itself doesn’t even show up. It’s as if nothing has been grouped at all.

We can however instantiate a new group in another scene, in which our group will behave like a cohesive object. To do so, select Add – Group Instance and select your (hopefully named) group. This will insert all your objects (and a null object) together as one into your current scene. It will even show up in your scene hierarchy now.

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Parenting

Parenting is what other apps call grouping: you move the parent and all children move, but you can move a child individually without the parent moving. Besides it tidies up the scene hierarchy via collapsable little icons.

To parent objects in Blender, select all objects, making sure that the last object you select will become the parent. If you’ve made a mistake in the selection order, hit A to de-select everything and start again. Click¬†Object – Parent – Object, or use the keyboard shortcut CTLR+P.

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When you do, a small pop-up window appears. Select Object again and you’ve built a relationship in the scene hierarchy.

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The object selected last will become the parent. Feel free to rename it for the whole group to make more sense. Now the familiar plus/minus icons let you collapse large scenes into something more manageable.

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Consider adding a null-object to the scene and select it last to make it the parent Рthis assures that you can still move the last object independently from all the others. You can do this under Add РEmpty.

 

Unparenting

If you no longer want an object to be part of the parent group, select it and click Object  РParent РClear Parent. This will return the object(s) back to the scene root. Alternatively, use keyboard shortcut ALT-P.

 

How to render with Depth of Field in Blender

Blender-DOF

Blender uses postwork to create a depth of field effect, much like Carrara does. The advantage is that after a long and complex render, depth of field can be applied after the fact without having to re-render.

I must admit that rendering with depth of field in Blender is not for the faint-hearted – I thought it’s best to take some notes while I still remember how it works.

Continue reading How to render with Depth of Field in Blender

How to render Motion Blur in Blender

BlenderMotionBlur

Motion Blur is the illusion of moving objects in still images. 3D applications create this effect usually by rendering several images of an animation and mixing them together as a blend effect. This is in contrast to an ordinary still image in which everything appears is focus as if it was shot with very fast film under ideal circumstances.

Here’s how to create this Motion Blur effect in Blender.

First we’ll need an object that will be blurred, and it needs to be animated. Nothing fancy, just moving for a few frames will be fine. Imagine the hand of a character, waving at the camera:

  • pose the hand¬†to the left
  • add a keyframe on the timeline
  • move the playhead¬†forward by 5 frames or so
  • pose the hand to¬†the right
  • set another keyframe
  • position the timeline back at the start (where the hand is facing left)

If we create a render now it will show the character with the hand to the left. Now let’s add Motion Blur: head over to the Camera Icon in the Properties Palette (those are the render settings Blender) and tick the box that reads Sampled Motion Blur.

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Note the two values you can set here: Motion Samples are the amount of images that are rendered and mixed together. Fewer images mean quicker render times of course, but it also depends on how fast your object is moving: a slow moving object will require more frames for the motion to be visible.

Shutter means the shutter speed of the camera. Higher values means a slower shutter speed, and hence more exposure during the movement. The default is 4 Motion Samples and a Shutter Speed of 5. Experiment with these values to get the effect you’re after.

Each animation is different and will require tweaking for the Motion Blur effect to look right. If the shutter speed is too high (or set higher than one), the images do not appear blended well enough:

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Too few Motion Samples will lead to a similar stutter effect:

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As a rule of thumb: increasing the Motion Samples will lead to a smoother effect. A longer shutter speed (up to 1) will expose more of the blended images. Shutter speeds above 1 will always create a stutter effect.

How to constrain an object to a Motion Path in Blender

Carrara has a concept of Motion Paths. Those are bezier curves to which another object can be constrained during animation. I’ve described how to use them in this article.

Blender has the same concept: create a curve (any curve will do), then add a Clamp To constraint to your object using the curve. Here’s how to do it:

Using the default scene, we’ll make sure our default cube can only move along the path of a circle. Let’s create one first by choosing Add – Curve – Circle. You can use any path object you like. Tweak the path as you like. I’ll leave mine on the floor for this example.

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Now select the object you’d like to constrain to this path. I’ll use my default cube by right-clicking on it. Next head over to the Properties Palette and select the little chain icon. Select a Clamp To constraint from the huge list of options (under Tracking).

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Under Target, choose your curve object – a Bezier Circle in my case. You can even define which axis you’d like to clamp and how strong you’d like the object to be influenced by the curve by tweaking the Influence parameter.

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Now try and move the cube¬†using any of the transform options: it behaves as if it’s safely mounted on the path. And there we have it: the cube now follows the path of the circle!

Cube

How to create keyframe animations in Blender

Keyframe Animations work a little differently in Blender than in other packages I’ve used. It all makes sense and is very intuitive – but I fear I might forget this, so here’s a quick guide on how animations work in Blender.

At the bottom of the interface is the standard timeline. Move the green line back and forth to move the playhead. To zoom in or out on the timeline, use the standard viewport controls (for example, gestures on a trackpad). Alternatively, there are two small grey dots at each far end of the timeline. Dragging those will also zoom the timeline.

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Anything that’s yellow here is a keyframe that relates to the currently selected object in the scene. Select a different object, and the keyframes for that object will show up. Those are just guidelines: to modify those keyframes the Graph Editor or Dope Sheet are probably better (we’ll worry about those in another article).

To set a keyframe, hover your cursor over the properties you’d like to save in this keyframe. For example, the location transform field in the currently selected object’s properties. Simply hover, then press I on the keyboard. This will set a keyframe.

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If no keyframe is set, but the object is animated, the field will turn green. If you’re currently on a keyframe, it’ll be yellow. Properties that are neither animated or have keyframe will appear grey. These are not part of your animation.

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Another way to set keyframes is by placing the cursor anywhere other than a property field and press I. This will bring up a context menu like this one, allowing us to set a keyframe for a particular property. Obviously move your object into position before you do this.

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Auto Keyframes

Another option is to create a keyframe every time your object changes on the current frame. This is how many other 3D applications work. In Blender you can switch this behaviour on and off as you need it, using the little red “record” button in the timeline.

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By default all properties of the object are saved in the keyframe – but you can restrict this by selecting what you’d like to record from the list next to the two little key icons.

And finally, to remove a keyframe, use the icons next to that list: the white key creates a keyframe manually, and the crossed out key removes it.

Animation