raikar designs

Illustrating Rainbow with Clone tool in Inkscape.


Rainbow and clouds.. by ~rockraikar on deviantART


After some gap, I'm back again. This post is about drawing a rainbow. There are actually two ways you can do it. One is by creating a rainbow color gradient and fill a semi-circle with it. The other is by using the tiled clones tool. Tiled clones happens to be one of the most powerful & interesting tool in Inkscape and here I am trying to draw a rainbow with it..

To start with, select the Spirals tool (F9 key) and draw a semicircle.

Let the settings be:
turns:0.50, divergence:0.00, inner radius:0.00.
Adjust the width, height and stroke width as in the image.
Now select the stroke color as the one with '?' (question mark :paint is undefined) in the stroke paint tab of fill and stroke menu. We need to do this because for changing colors of clones using clone tool it is necessary that the paint is undefined for the object. Now,the arc/semi-circle will be invisible.



Next is the cloning step.
Keeping the arc selected,
Go to edit->clone-->create tiled clones. The following settings needs to be updated:


Symmetry:P1 simple translation.
7 rows and 1 column
Shift: for X all the values are zero. for Y the per row field should be -98.5
Scale: scale X per row is -1.6, scale Y per row is -0.7, all others are zero.
Color: Initial color be red, for per row field change the H value to 13.5. Rest all should be 0.
We wont be using rotation blur & opacity so we can leave them as they are.
Now press create, your rainbow is ready.
Give it a little blur and decrease its opacity.


You have your Rainbow. You can add a few clouds like the ones here. Apply a little blur to these clouds and it will look a bit realistic.
Happy Inkscaping...

Drawing shadows along with objects gives an illustration some amount of reality. I was trying to illustrate shadows and felt like sharing some thoughts that I had. Probably a beginner may find it interesting. Anyways here it is...

To draw a shadow, one needs to be clear about properties of three things:
1) source of light (position, brightness, size)
2) the subject itself which casts the shadow (position, shape & size)
3) the surface on which shadow falls (position, shape & size)
Now how do these properties affect the shadow cast by the subject... ?
These two videos give you a basic idea of how shadow can be drawn and how the properties affect them. A must see... How to draw shadows and Drawing perspective shadows.

Some points to be noted are:
Size of shadow depends on distance between the source of light, object and surface of shadow. The size of the shadow increases as the distance between source of light and object decreases.
The shadow appears blurred if either there are many sources of light or if it is far from the subject.
The position(angle) of the source of light decides in which direction the shadow is cast.

The shape of shadow is also defined by the surface on which shadow is cast. shadow is irregular on irregular surfaces.

The 3 dimensional subject is cast as a two dimensional shadow whose shape is defined by the relative position of subject and source. For example see what objects can cast a square shadow and what shadows a cube can cast ... That would give you an idea.

After getting basic idea about shadow, the next point is how do we illustrate a shadow in Inkscape.

The basic method is duplicate the subject to create the shadow, give it a grey color and decrease its opacity. Then do the transforms like skew, stretch and move. What transforms and how much you need to perform depend on the properties of source of light,subject and surface that you saw earlier.

For 2D image editing softwares, the above idea can give good results for flat or simple sjubects. When the subject is a 2D illustration of a complex 3D object some amout of imagination and manual editing of the nodes of shadows is necessary.



Here is a small how to for illustrating shadow for a human figure. You can apply the technique for other objects also.

1) Draw ellipses using ellipses tool, rotate and arrange them as above to get a human form.

2) To draw the shadow, duplicate the subject (select subject and press ctrl+d)
select all the ellipses and do a path->union.
give it a grey (888888ff) color fill and 75% opacity.

3) Group the ellipses of subject (Ctrl+g)
For time being, place the shadow object above the subject.
Align(ctrl+shift+a, center along vertical, center along horizontal axes) them both so that they overlap each other completely.

4) Angle of source of light:
Click on the shadow layer twice, you will see the handle for skew operation.
Play with the skew operation holding shift key. This will give the angle at which the shadow is formed.
Depending on the position of source of light you can settle for a shadow.

5) Elevation of source of light

Now click on the shadow object once, you can see the squeeze or stretch handle.
play with this handle. this gives the elevation or the height of the source of light.
settle for required elevation.

So now we have a shadow of the object on a flat surface(floor).
What if there is a wall some distance behind the man, would the shadow be the same ?

lets see how to illustrate that.

A) Select the shadow and the wall surface and duplicate them.
Tthen do a path-->intersection. give this new shadow object the same fill and opacity as that of the shadow.
Send the old shadow to bottom (select shadow and press end key)
We need to do a skew to the new shadow as we did earlier for angle of shadow, this time the shadow must be vertical as below.
B) The shadow that you got is not a perfect one, we need to do the stretch operation.
Decrease the opacity of the wall so that you can see the old shadow.
Draw a reference line from the old shadow to the man's head.
Now stretch the new shadow as we had done earlier until it touches the reference line.
Now reset the opacity of wall and delete the reference line.
The final result


Applying the same technique you can illustrate shadows on complex surfaces. Here is an example of shadow on steps.

I wanted to have a globe with those latitudes & longitudes on it.I was doing it manually earlier by duplicating and resizing, but there's the clone tool to do that easily. Here is a tutorial on how to do a simple globe with latitude/longitude. I have a very bad color sense so you can surely do a better job with colors. :)
Here is what we can have



1) draw a perfect circle (holding ctrl key) with no fill and black stroke.
2) Now we need to do some cloning.
Select the circle and go to edit-->clone-->create tiled clones.
Select 'simple translation' for symmetry and following settings for shift and scale.

3) We will get something like this.
Now select them all and go to edit-->clone-->unlink clone (or shift+alt+D)

Illustrating objects to give it a 3D look requires a few transforms, unions, differences & most importantly the gradient. Here is a simple circle you can draw. The technique used here applies only for basic shapes and that too for particular orientations.



Only 3 objects is all you need to get this cool 3D looking ring.
here are the steps:

step1: Draw an ellipse (let the opacity be around 75% for our visualization)
Duplicate it and scale it to a smaller size holding shift & control.

step2: Duplicate these ellipses and move them out.
Duplicate them once more and shift them vertically up by few pixels(as in image)


step3: Select the two ellipses, duplicate them and move them out.
then do path-->difference
We have our object 1.


step4: Select the two smaller ellipses from the object in step 2, duplicate them and move them out.
Now do path-->difference. (check out which object should be above which one )
We have our object 2.


step5: Select the two larger ellipses from the object in step 2, duplicate them and move them out.
We need to draw a rectangle. Its width same as the width of the ellipse
and height equal to the vertical distance between the ellipses.
Select the lower ellipse and the rectangle and do path-->union. Move this object to bottom.
Select both these objects and apply path-->difference.
We have your object 3.



step6: Now what you need to do is assemble these objects.
Zoom in and arrange them.


step7: Next we need to color them.
for object 1, a plain fill is OK.
for object 2, we need a linear gradient with variation 'dark to light to dark'
for object 3, we need a linear gradient with variation 'light to dark to light'
make the opacity to 100%



PS: when aliging objects, there may be some gaps/white spaces between them.
to hide it, give the object a stroke with the same color/gradient of the fill.


You can do similarly for triangle and square shapes. A representation is here in the PNG & SVG files.

Grouping these objects, you can do cool 3D illustrations like this and many more....
the svg.

For complex objects, and even for simple objects with different orientations, above technique is not suitable.Will try to cover that in next post.
Happy Inkscaping :)