Pseudo 3D with Gimp

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Original in fr André Pascual

fr to de Katja Socher

de to en Katja Socher

AboutTheAuthor:

Originally an industrial designer, now a professor of production, he teaches CAD. Computer graphics, especially 3D graphics, is one of his passions.

Abstract:

Gimp is a software exclusively 2D, but with a few tricks and thanks to the numerous tools that are available, it is possible to create an image in pseudo 3D.

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To get to the result of the example given in figure 1, four steps are necessary:

1. Create a background with a perspective effect for the ground
2. Create a text with an effect of a magnifying glass on the vertical wall
3. Create a reflexive pseudo sphere
4. Polish it by adding shadows, impressive splendour and lenses.

Create the ground

Choose the background pattern

I assume that the pattern "circuit" is available in Gimp. If this isn't the case, any other motive (the list in Gimp appears by clicking on <File><Dialogs><Patterns> or by pressing [Shift+ Ctrl+ P] ) will do for the matter. In this list, press the pattern to get the image shown in size 1:1. This shows also the name of the pattern at the top of the window.

If you want to reproduce the suggested image exactly and the motive "circuit" doesn't exist in Gimp, you can get it. For that open Gimp, load the file /opt/kde/share/wallpapers/circuit.jpg and save it with the extension"pat", choose in the list of formats <By extension> in the menu <Save Image>, that is /usr/local/share/gimp/patterns/circuit.pat.

The pattern will be available the next time Gimp is started. It should be noted that the suggested way here is for KDE 1.1.1 and Gimp 1.0.4 installed on Mandrake 5.3; it can be different in other distributions.

Before starting recall that if you are unaware of the meaning of an icon in the toolbox you only have to put the cursor over the icon in question to see a help text appearing. Recall as well that a double-click on an icon opens the dialogbox <Tools options> specific to the tool chosen. Recall in addition that a straight click on an image opens the pop up menus that consist of all the manipulation tools, from saving to filters and other Script-Fu... And finally recall gimp has shortcuts for all the operations that can be choosen from menus. Some of them are very useful: new, open, close, quit, copy, paste, cut, undo, redo...

Prepare the background

• Start Gimp, if this isn't already done.
• Prepare an empty file with File> New> 640x480 >Background> OK
• Open File> Dialogs >Patterns and choose Circuit (or something else)
• Fill the actual background with white by double-clicking on Fill (fill bucket)> Pattern Fill
• Click in the active window.

That's it.

As it will be necessary to have one image for the wall and one for the bottom, save the work in jpeg quality 1.00 (without compression; we will later compress the final image) first as 1.jpg, then a new one as 2.jpg. We now have two identical images, 1.jpg and 2.jpg, image 2 is shown on the screen. It will serve us to create the ground.(See Figure 2)

Create the ground

The final image will have a dimension of 400x400 (arbitrary choice). You can distort 2.jpg which is shown on the screen and which is much bigger (640x480), with the help of the magnetic guides. They are activated by clicking in the rulers that border the image. Click on one ruler and then press the left button of the mouse, hold it and move the pointer to the work zone. This will show a a dotted red line moving, horizontal or vertical depending on the ruler on which you have clicked. Place the guides as shown in the image below. This dotted line becomes blue when it is unselected: it is a magnetic guide that draws the mouse pointer or the border of a selection when you approach it.

• Place in this way a horizontal guide at 300 pixels from the origin, then two horizontal guides, one at 120 and the other at 520.
• Select a layer by a click on the image and Select> Select all
• Double-click on Transform tool to get the options for this. In the menue <Tools options> that appears choose <Perspective>
• Distort the selection to get a trapeze while making the corners high/left of the selection coincide with the left intersection of the guides. Attention this is a cpu power intensive operation and calculation will need some tim. Wait until it is finished before clicking somewhere else.
• Pull then the corner high/right of the right intersection of the guides. You obtain an isocele trapeze (See Figure 3)
  
  Figure 3, the ground
  
  
• Iconify the image or send it to another desktop. As a precaution can you save it also.

Create the front wall

• Recall image 1.jpg
• Place a horizontal guide at 400 pixels, and two vertical guides, one at 120 and the other at 520.
• Select the layer by clicking> Select >Select all
• Select Transform Layer or Selection and, in <Tool option> which should still be open from the former call, choose Scaling.
• Distort the layer so that a square of 400x400 ends with its borders at the guides.
• Now add a transparent layer by clicking > Layers> Layers and channels >New layer. Place the ground on the layer, then you can call it "ground" by clicking on the name which is "new layer" by default. (See Figure 4)
  
  Figure 4, adding the ground to the front wall
  
  

Assembling wall and ground

• Copy the trapeze-shaped ground of 2.jpg in (use the feather tool click on each summit of the trapeze, finish by clicking on the point you started with and then inside the trapeze )
• To paste it into 1.jpg, in the layer "ground" which we have just created, click on > Edit >Paste. The bottom places itself in the empty layer. Shift it such that the interior corner of the selection coincides with the horizontal guide.(See Figure 5)
  
  Figure 5
  
  
• Flatten the image by clicking> Layers> Flatten image. Now the image consists of only one layer.
• Cut the image to a dimension of 400x400 with the tool Crop of the toolbox (it will automatically be pasted to the magnetic guides)
• Add a layer "Text"
• Save (just for security reasons) as 3.XCF (the format of Gimp preserves the layers.

Create the text

Produce a text-logo

• Click on Xtns> Script-Fu> Logos> Crystal
• Enter the text "LOUPE" ("Magnifying glass" or something else), Font "Cooper" (or other), Font size "105", Background "/opt/kde/share/wallpapers/circuit.jpg", OK.
  • Note: the font "Cooper" is part of the package "Freefont" and isn't installed per default in all distributions. It is a good idea to install this package as well as the package "Sharefont" which are essential for a the Logos of gimp. (101 vectorial fonds are available from Christoph Lameter, <clameter@waterf.org>.
• The logo is produced; the letters are textured with the same motive as the wall but in a bigger scale than that of the wall which was reduced. You get a magnifying glass effect.
• The logo consists of several layers, of which one is called "Background". This is of no use, you must remove it by double-clicking > Layers> Layers & channels> Delete layer, the layer that will be removed must be selected. You can select it by clicking on the button: it will be in the blue splendour.
• Assemble the other layers by clicking> Layers> Merge Visible Layer (most of all don't use Flatten image: you would loose the transparency of the background) (See Figure 6)

Assembling the text

• Copy the text in the press-paper
• Paste it into 3.XCF (which hasn't been closed) on the layer "Text"
• Place it according to demand (that what can reasonably be seen through the transparency must correspond more or less with the drawing of the wall which lies behind. See Figure 7).
  
  Figure 7
  
  
• Save as 3.XCF (necessary this time because we will now divide the image shown on the screen without wanting to lose what we just made)

Create the reflexive sphere

Prepare the reflexion

The sphere must reflect the text on to the front wall, that is, it must be invers to the original and rounded on the sphere.

• Select the text with a rectangular selection, the layer "Text" is the active layer
• Select the symmetric vertical tool by double-clicking on Flip layer or selection> Vertical (The Flip layer is in the toolbox)
• Define the selection to distort it with the cursor which will be replaced at this moment by a up/down arrow

Drawing of the sphere itself

Now it will become more delicate.

• Flatten the image by clicking >Layers> Flatten image
• Use the circular selection tool (press Shift and at the same time move the mouse so that you obtain a circle and not an ellipse), so that at least 3 letters are inside the selection and are situated in the upper part of the circle.
• Distort the selection by clicking > Filters> Distorts> Whirl and Pinch with the following values: "whirlangle:0", "Pinch amount:-1", "Radius:2" (they are the chosen values for the desired result and are obtained by numerous trials: there exists no formula in this field)
• Validate and restart the operation with the same values (See Figure 8)
  
  Figure 8, Whirl and Pinch
  
  
• The selection is always active, copy it into the press paper. You can now close the drawing without saving.

Assembling sphere and background decorations

• Recall file 3.XCF
• Create a layer called "sphere"
• Paste the sphere and place it (even change its scale) so that the reflexive letters correspond with the letters of the wall.
• Save as 3.XCF

Polishing the work

Create a shadow on the sphere

• Add a layer "shadow sphere", transparent, opacity 90 (there is always the possibility to change this value), mixing mode "Normal"
• Place 4 magnetic guides tangent to the sphere.
• Carry out a circular selection with the help of the guides (starting at the intersection high/left to the intersection low/right). The selection must surround the sphere.
• Double-click on the tool Fill with a color gardient; in the menu <Tool options> choose "Blend: FG to transparent" and "Gradient: Linear".
• Select a black colour if this isn't already done
• Fill the circular selection with a degradation of black ->transparent by drawing a horizontal line which goes from the extreme right part of the diameter of the sphere to the extreme left part of the sphere (you must imagine the diameter: it is not represented).
  The shadow is in its position. Make some trials with the mixing mode of the layer "shadow sphere", to see how the black pixels behave with the ones on the layer below.
• Save the work when you are satisfied.

Create a moving shadow on the ground

• Add a layer "shadow ground", transparent, opacity 80
• Imagine the shape of this shadow: it is a very flattened ellipse. To obtain it draw an elliptic selection (without pressing) and place it so that the extreme left line of the big axe (horizontal here) coincide with the point of contact between sphere/ground. You can use the magnetic guides for help (See Figure 9)
  
  Figure 9
  
  
• Double-click on the tool Fill with a color or pattern; in the menu <Tool options> choose "Mode: Normal" and "Fill Type: Color fill".
• Choose a very dull green (R:18, G:35, B:14 for example)
• Fill the selection with this green.
• The resulting shadow is not realistic because the environment is too clear. A realistic shadow is always more diffuse on its borders. This can be obtained in two steps:
• In the selection that is always active, click > Filters> Blur> Motion Blur> Radial with the values "Length: 35" and "Angle: 45"> OK
• Unselect, then double-click> Filters> Blur> Gaussian Blur (RLE) with the default values > OK

Create a specular reflection on the sphere

• Add a layer "reflection"
• Carry out a selection that is big enough in crescending from the left frame of the sphere with the Feather tool (more difficult with the lasso).
• Select a white color
• Paint it in degradation FG->Transparent with the same method as before, but from left to right.
• Mix the layers with the mode "overlay". If the effect isn't emphasized enough, paint it two or three times with the same method.

Create a lens effect

• Flatten image
• Place two magnetic guides so that their intersection corresponds with the center of the reflexion (See Figure 1), and shift them back on the rulers to their position on X and Y
• Double-click >Filters> Light Effects> Flare FX
• Enter the back-shifted values in X and Y in the parameters "Center of Flare FX". You can also distort the cursor with the mouse on the button of the image and then place the center of the reflexion visually.

The final touch

Conclusion

Voilà. The work is almost finished. I write almost because when we look at it there are surely mistakes, approximations... All creators have their own view of the objects and their own style. Everyone will have a different opinion.

Everyone should be amused.

Because Linux, and more Gimp, or evenmore the enthusiasm of the creator should not be neglected as a source of amusement.