Lesson 11: Multiple animations (part 3)

In the previous lesson, we looked at a sequential animation where a pair of doors opened, followed by a drawbar sliding across. But the animation only worked in one direction because the opening doors were linked to the onClick handler so they always began first, even when reversing the animation. Now we shall look at how to make the animation sequence work correctly in both directions in a copy of the last version (now called "DC7").

The principle then is to have one animation, the Timeline, and link each door and the drawbar to this attribute. Let's start by examining the values we are working with.

Door 1 (LeftAngle) begins at -90 when open and ends at 0 when closed
Door 2 (RightAngle) begins at -90 when open and ends at -180 when closed
The Drawbar (BarPosition) begins at -210 when drawn back and ends at -5 when closed
The Timeline will go from 0 to 100 in 1.1 seconds.

As a chart, this is:

Time	0 seconds	0.5 seconds	0.6 seconds	1.1 seconds
Timeline	0	45%	55%	100%
LeftAngle	-90	0	0	0
RightAngle	-90	-180	-180	-180
BarPosition	-210	-210	-210	-5
Process	Start doors	End doors	Starts bar	End bar

Notes: the % in the Timeline isn't included when we enter actual values, it's just there to show that the Timeline is like a counter going from 0 to 100% (completed). The Process when reversed, would be "End Doors - Start Doors - End Drawbar - Start Drawbar".

The first thing to do is to remove all the formulas and functions from the main "DC7" attributes (but leave the formulas in the subcomponents linking the Doors' RotZ to LeftAngle and RightAngle, and the Drawbar X position to BarPosition). Your Components Attributes window should look like this:

Now we add the single animation to the onClick attribute:

ANIMATECUSTOM("Timeline",1.1,0,0,0,100)

This is almost the same as the one we used in the previous lesson except that Timeline is now going from 0 (%) to 100 (%) and the easing is zero-zero since I want no change in acceleration. Clicking on the component now seems to have no effect but, if you make the Timeline visible, you can see it changing from 0 to 100 and back on each click.

(If you have forgotten how to make an attribute visible, click on the Details button on the right of the Timeline which looks like a menu combined with an arrow (see image below). Change "Display Rule" to "Users can see this attribute" and Apply. Now, if you have the Component Options window open when you click, you can see the value of the Timeline changing.)

The Details button, used to make the Timeline attribute visible

The formulas

Now for the formulas. If we start with the left door, we see that when Timeline is zero, LeftAngle must equal -90 and, when Timeline is 45, it must equal 0. If we add 90 first to get rid of the negative numbers (which can be confusing) we find that

0 Timeline = 0 LeftAngle

45 Timeline = 90 LeftAngle

and the formula is therefore:

LeftAngle = (Timeline * 2) - 90

(The brackets aren't necessary because of the rules of algebra but they make things clearer.)

When working out a formula, remember to add some intermediate angles in the calculation to check. In this case. 22.5 would be halfway along the Timeline and the LeftAngle would be -45 which, when I check the calculation, works out correctly. This is where the spreadsheet comes in useful.

The formula that we need to enter in the LeftAngle then is:

=IF(Timeline>45,0,Timeline*2-90)

Meaning: if the Timeline is greater than 45, set it to zero (closed), else animate it.
 Enter this, click on the component and you should see the left door open and close.

Note: the fact that the Timeline value is exactly half the LeftAngle is coincidence. It makes it a bit easier but isn't important.

For the second door, we need:

0 Timeline = -90 RightAngle

45 Timeline = -180 RightAngle

A formula I worked out for this is:

RightAngle = 0 - ( 90 + ( Timeline * 2 ) )

 thus

=IF( Timeline>45, -180, 0-(90+(Timeline*2)) )

So now, clicking the model opens both Doors.

Note that, after the Doors open, the animation runs on for 0.6 seconds with nothing apparently happening so don't click again too soon after the first click. Allow the animation time to finish.

Finally the Drawbar where we need:

55 Timeline = -210 BarPosition

100 Timeline = -5 BarPosition

Thanks to Excel, I find that the formula is:

BarPosition = (4.5556 * Timeline) - 460.5

so the formula for BarPosition is:

=IF(Timeline<55,-210,4.5556*Timeline-460.5)

Now, click on the component and two animations work together, both opening and closing.
The final settings:

Creating timelines and linking multiple animations is tricky, involving caeful maths and logical thinking, but the results can be very pleasing.

The final model is available on 3D Warehouse at https://3dwarehouse.sketchup.com/model.html?id=u9644e7be-7be5-4764-a2e6-785d96c41259

Lesson 10: Multiple animations (part 2)

Sequential animations

While simultaneous animations are easily produced by placing them together in an attribute, the sequential animation is more complicated. Basically one animation, often an abstract custom attribute, is begun as normal, usually by an onClick formula, while the others are controlled by accessing the value of the first.

As an example, let's elaborate the opening doors we created in Lesson 9. In castles, the main doors were often secured by sliding a wooden beam across when closed so we shall add this to the twin doors. Our animation will consist of the two doors closing and then, once the doors are closed, the drawbar will slide across.

First duplicate the two door component we created in "DC5" and rename it as "DC6". Within the component, create a rectangle named "Drawbar" and position it in the final, closed position as below. Add the X attribute to the Drawbar and make a note of its value.

 Next we need to move the elements to their 'start' postion, so change the Doors' "RotZ" values so they are both open (remembering that we are changing the custom attributes "LeftAngle" and "RightAngle", not the RotZ directly). Then change the Drawbar's X position so that it is drawn back as shown below.

The first animation is straightforward, keeping the existing "onClick" to rotate the doors. The second animation involves the Drawbar sliding across by changing the object's X position. But we don't want this to happen until the doors are closed so how do we accomplish this? One technique is to create a custom attribute which will have a timeline and the animations are based on this, determining their values from this attribute. In this case, because the doors start at the same time as we click it, we can leave them as they are, but the moving of the Drawbar will need to controlled by this.

Before we create anything though, we need to get out a pen and paper (or spreadsheet) and work out some timings. The doors use the Animate function which occurs over half a second so let's say the Drawbar animation will start at 0.6 seconds (to allow a more realistic slight pause between the actions). The Drawbar animation can also take half a second so the total length of the full animation is 0.5 + 0.1 + 0.5 = 1.1 seconds.

In my model, the X position of the Drawbar is -210 when withdrawn and -5 when closed so, putting these together in a table:

Time	0 secs	0.6 secs	1.1 secs
Drawbar X	-210	-210	-5
Timeline	-456	-210	-5

Now comes the complicated part of working out a formula. I worked out the Timeline figures so that the Drawbar X position matches the Timeline but, obviously we don't want the Drawbar to move until the Timeline reaches -210 so we need to add an IF formula which says (in English):

If Timeline is less than -210, Drawbar position is -210, else Drawbar position is equal to Timeline.

As a SketchUp formula, it is (notice no quote marks around the attribute names:

=IF(Timeline<-210,-210,Timeline)

Finally we simply link the Drawbar position to the Timeline.

The final formulas are shown below:

You may have noticed the CUSTOMANIMATION that controls the Timeline animation. Because we want an odd number, 1.1 seconds, we can't use the standard ANIMATION types so have to use a CUSTOMANIMATION. The parameters for this formula are, compared to the normal ANIMATION:

ANIMATION(attribute, state1, state2 ...)

CUSTOMANIMATION(attribute, time, easein, easeout, state1, state2 ...)

The only thing that might be puzzling is the easein and easeout. These determine the acceleration of the animation with 0 being the fastest and 100 being slowest. The default easein and easeout for an animation is 0 and 100 which means the animation starts fast and slows down, rather like a ball being thrown in the air. Values of 100 and 0 would mean it starts slowly and speeds up (like a rocket taking off).

The details we enter are:

ANIMATECUSTOM("Timeline",1.1,0,100,0,-456,-5,-456)

which means the Timeline value changes over 1.1 seconds, starting quickly and slowing down, going from -456 to -5 on the first click, then back to -456 on the second click.
If you click on the component now, you should see doors open and then, after a pause, the drawbar slide across.

The reverse  animation doesn't work properly with the doors opening before the Drawbar has slid back but, to have the animation working both ways requires a more complicated arrangement. For this to work, you would have to link the animations of both the Drawbar and the two doors to the position of the Timeline which is much more complicated. Maybe you can think about how to achieve this. I shall show my method in the next lesson.


The completed component is available on 3D Warehouse at https://3dwarehouse.sketchup.com/model.html?id=ud59967fd-643b-4621-aeb5-d1cbbbc9fb19

Lesson 9: Multiple animations (part 1)

Up to now, all the animations we have created have been simple, one-step animations: the window swings open or close. But some of the more impressive effects are multiple animations and there are two sorts: simultaneous and sequential.

Simultaneous animations

Animations where two or more changes occur at the same time are easy to create. All that is necessary is to add the different effects in the same onClick (or other) area, separated by semicolons, e.g.

ANIMATE("X",0,50); ANIMATE("Y",0,100)

The order is irrelevant as they start together. (They may end at different times depending on which type of animation you use.)

As an example, we shall create a pair of double doors which open simultaneously. So create a door with a cutaway corner (see image below) and make it into a component. Duplicate it and flip the copy along the red axis so that the axes are on the outside (this is where the cutaway shape comes in useful). Then make the two doors into a component ("DC5"). It should look something like this:

 
To open the doors, we add an onClick to the DC5 component to animate them. How do you know which of the two sub-components is which? Well, if you add the X attribute to both doors, you will see that one has a X position of 0 (the left) while the other has a value twice the width of the door. You can also look at the RotX of both which will show 0 and -180.

The problem with the model at the moment is that we have used two copies of the door component; consequently  they both have the same name. If we rename one, they both get renamed. If we animate the RotX, SketchUp can get confused as to which we are referring to. We could have used groups which would be separate but, because the doors are identical, it is better to use components.

To get around the problem, we can create two custom attributes in the top level "DC5" to hold the angles for both doors: LeftAngle and RightAngle. We enter 0 into the first and -180 into the second, then link the RotZ of each door to its appropriate value.

=DC5!LeftAngle

and

=DC5!RightAngle

If we now enter different values into LeftAngle and RightAngle, we should see the doors adjust their angle.

Finally, we enter the two animations into the onClick box of "DC5", separated by a semicolon. The first changes LeftAngle, the second changes RightAngle. If we click the doors with the Interact tool, the doors should open and close together.

If your component isn't working, check it against these formulas:

The model, DC5, is available on 3D Warehouse at
https://3dwarehouse.sketchup.com/model.html?id=u2ba92957-10fd-48bf-b004-9d9d4219e20e

In the next lesson, we will look at how to create sequential animations where they do not occur at the same time.

Lesson 8: Limiting the Scale tool, and other attributes

This week, a break from creating dynamic components with a look at the other attributes in the Component Attributes window. We have already seen many of them and most are self-explanatory but let's look at some of the others.

The group titled "Component Info" are all to do with what appears in the Component Options window. The position of the various attributes are shown below. You can also see a piece of italic text in the description and this is to show that you can use HTML codes in any of these areas. Only certain codes are available but they can make your text look more interesting and you can add links to your webpage, for instance.

Available HTML codes
    <a> anchor
    <b> bold
    <i> italic
    <u> underline
    <strong> bold
    <em> italic
    <p> paragraph
    <br> line break
    <ol> ordered list
    <ul> unordered lis
    <li> list item
    <font> font size, colour, etc

The "Form Design" group have similar uses. "ImageURL" allows you to replace the default thumbnail with your own image. The "DialogWidth" and "DialogHeight" determine the size of the Component Options window. (If you are working on a large screen, don't make the "DialogHeight" too large – remember other people will have smaller windows.)

The "Hidden" attribute simply hides or shows a subcomponent. This could be useful where, for example, you have a vehicle with different designs – a lorry that could be flat bed or enclosed. I also used it in a restaurant dining table/ chair set so that you could have variable options – one chair, two chairs opposite, two chairs side-by-side.

The final attribute "ScaleTool" is often used with dynamic components to disable or limit the use of the Scale tool with your component. As an example, imagine you have created a ladder that adds extra rungs as you lengthen it (increase the LenX). It would be all right for the Scale tool to be used to make the ladder longer but not to change the other dimensions (LenY or LenZ). That would distort the rungs and supports. With the ScaleTool attribute, you can disable some or all of the ways the Scale tool can be used.

To do so, double-click the "ScaleTool" attribute or click the menu-arrow icon to the right. The screen below appears.

As you click on the checkboxes, you can see the handles appear and disappear meaning that the Scale tool cannot be used in that way. The easiest way to understand is to deselect some of the checkboxes, click apply, and then try to scale your component with the Scale tool. The setting below shows how the checkbox combination is mirrored when using the Scale tool.

Lesson 7: Dynamic copies

Previous lessons have looked at simple dynamics such as changing a single attribute but this lesson will tackle something more complicated and which can sometimes take a while to get your head around – dynamic copies.
As an example, imagine a ladder with 10 rungs spaced 50 cm apart. If you double the length of the ladder, you don't want 10 rungs spaced a metre apart, you want 20 rungs spaced 50 cm apart. Similar needs come with sets of stairs, fences, furniture with multiple drawers.

For this tutorial, we shall again keep things simple so you can understand the principles without getting confused by details. Start by creating a block 100 x 50 x 200 on each side, group it and name it "Wall". Then create a step 50 x 10 x 30, make it a component (because it will be repeated, unlike the wall), and name it "Step". Position the step at the bottom edge of the block (see below), then select both and make it in to a component "DC4".

 Notice that we have only made one rung. All the others will be handled and duplicated automatically by formulas but, before we do that, we shall add a couple of custom attributes. Under the DC4 component, add two custom attributes: "TotalHeight" and "Spacing". The first determines the total height of the component so enter "50" for the moment. Then, under the Wall element, add the attribute LenZ and enter into its box the formula:

=DC4!totalHeight

The height of the Wall is now linked to TotalHeight so we can change the height of the subcomponent Wall from the main DC4 component. The Spacing attribute determines how far apart the steps are so enter 50 at the moment (so we have one step per 50 cm of wall height).

If we now enter 100 into TotalHeight, we should see that the wall gets higher but nothing else happens. We need to handle the duplication of the steps to allow for the extra height and this is determined by the attribute called "Copies" (under OnClick in the popup menu). So add the Copies attribute to the Step element (since we are making copies of the Step and enter the formula:

=DC4!totalHeight/DC4!Spacing

This means that the height of the wall is divided by Spacing to determine the number  of total steps. If you try different values in TotalHeight, you should see the value in Copies change:

TotalHeight	Formula	Copies
50	50/50 =	1
100	100/50 =	2
150	150/50 =	3

So the number of steps is increasing with the height of the Wall. Wait, you protest, I can only see one Step! Well there really are the same number of Steps to match the Copies value but they are all in the same location as the original Step so you can't see them. What we need to do now is change the Y and Z positions of the copies of the Step so that they are positioned separately. This is handled by a new, read-only attribute which is not normally visible called COPY. This holds the number of each copy so the original Step is numbered 0, the next 1, then 2, and so on. If you view the X, Y and Z positions of the Step, you see that it shows X=100, Y=0 and Z=0. If we start with the vertical position of each Step, we already have the Spacing so we simply set the Z position to:

=DC4!Spacing*COPY

The results would be:

COPY No.	Formula	Z Position
0	50*0 =	0
1	50*1 =	50
2	50*2 =	100

etc.

After entering this formula, you should see the steps suddenly appear next to the wall.

 You can change the horizontal position as well by adding the same formula to the Y position. Now, as you change the TotalHeight, you will see Steps magically appear or disappear.

  
TIP if you double-click and open the component after these copies have been made and select one of the them, you will see the COPY number in the attributes (below)

If your component isn't working, here are the settings below:

Obviously the positioning isn't quite right and here comes the mathematical bit. You need to adjust the formulas to space things correctly, maybe adding on an offset or allowing for the thickness of the step. One of the best ways to go about this is a sort of reverse engineering – draw the final component on paper, working out what the positions of each step would be and work out a formula which would produce that. A spreadsheet comes in very useful here.

Sketch diagram of the finished dimensions

The final formulas which space the Steps correctly are:

Y position = (200-30)/Copies*Copy
Z position = (DC4!totalHeight-10)/Copies*Copy

As before, the component, DC4, is available on 3D Warehouse at

https://3dwarehouse.sketchup.com/model.html?id=udd41c4eb-9a36-43ea-81fa-c49421426634