Google SketchUp Cookbook phần 7 pdf

In the “Other Uses” section, you’ll see how a single alpha age can be used to simplify an Eiffel Tower model, and how to use an alpha image to make a ring of trees.Download my Balcony Ho

Creating and Editing a Unique Texture | 217

Creating and Editing a Unique Texture

The advantage to making a unique texture is that you can add detail to a particular face without changing all faces with the same material, and still keep the geometry simple For example, you could edit a stone material to have different-colored stones, which would be difficult to achieve

by adding extra geometry; you would need different materials for each new face

In this example, you will use your graphics editor to add a sign and paint some of the bricks of just one building in a row of identical buildings

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Warehouse (Figure 8-77) This is a row of shops You will edit the material of the middle shop

of the original material, and you can change it if you want

To edit this material, right-click either on the

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thumbnail in the Materials window (in Windows only) or on the material itself in the model Choose Edit Texture Image from the pop-up menu

Figure 8-78

The new material appears in your default

graph-4

ics editor Make some changes to the image Figure

8-79 shows added text and some painted bricks

Figure 8-79

Save the edited image and return to SketchUp The

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middle façade now has the sign and painted bricks

(Figure 8-80) Those yellow bricks would have

taken more work to create within SketchUp and

would have increased the file size

Note

The thumbnail for the new material in the Materials window

will reflect the changes you make in the graphics editor.

Using Alpha-Transparent Images | 219

Note

You can use alpha-transparent images to create 2D Face era components, which are simple 2D cutouts that always face the same direction wherever you orbit, giving the look and feel of a 3D object For more information and for a discus- sion of a problem with alpha images related to shadows, see Recipe 9.4.

Cam-The Fencing folder of the Materials window has a few materials with transparent backgrounds To find more,

you can search the 3D Warehouse for alpha images or

its variations The 3D Warehouse also has numerous models of alpha-transparent trees and plants

In the main example, you will create a railing around

a balcony by using an alpha-transparent image In the

“Other Uses” section, you’ll see how a single alpha age can be used to simplify an Eiffel Tower model, and how to use an alpha image to make a ring of trees.Download my Balcony House model from the 3D

up the first floor (Figure 8-82)

Erase the top face of this new box, which leaves just

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the three vertical walls (Figure 8-83)

Open the In Model folder of the Materials window

transpar-The greatest advantage of alpha-transparent images is that they enable you to reduce your file size by using graphics instead of geometry A 3D tree has a much higher number of edges and faces than a 2D face painted with an alpha-transparent tree A fence with repeated posts and pickets is much more complex than a 2D face painted with an alpha-transparent fence image

Paint one of the railing faces with the iron fence

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You can see through the face, but the fence is the

wrong size (Figure 8-84)

Use texture positioning in Fixed Pins mode,

drag-6

ging the red pin to change the starting location, and

dragging the green pin to change the scale, so that

the image fits the face (Recipe 8.9) Right-click and

choose Done when finished

Figure 8-84

Sample the edited material (press the Alt key in

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Windows or Cmd on the Mac while the Paint tool is

active, and click the positioned texture) Then paint

the other two faces (Figure 8-85) Just like when

you paint with translucent materials (Recipe 8.7),

alpha-transparent images are applied to both sides

of a face (But you could override this by painting

one side with a different material.)

Figure 8-85

To make the railing look more realistic, hide its

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vertical edges and top horizontal edges (select these

edges, right-click on one of them, and choose Hide

from the pop-up menu) Figure 8-86 shows the

completed railing

Figure 8-86

Using Alpha-Transparent Images | 221

Other Uses

For a great example of how using an alpha-transparent image can reduce your file size, download Google’s Eiffel Tower model from the 3D Warehouse (Figure 8-87) It looks complex, but it’s actually a simple model painted with an alpha image This model can be found

in my 3D Warehouse collection for this chapter

Figure 8-87

You can find the image in the In Model folder of the Materials window (Figure 8-88) This image was ap-plied to all four sides, using material positioning in Free Pins mode to adjust the image to fit each face Free Pins mode is described in Recipe 9.1

Figure 8-88

To see the unpainted model, switch from Shaded with Textures mode to Shaded mode (Figure 8-89)

Figure 8-89

You can also use a single alpha image of a tree to make

a ring of trees Figure 8-90 shows four vertical faces

painted with a tiling tree image

When the edges of the faces are hidden, it looks like a

group of trees

Figure 8-90

You can use Push/Pull on the faces to make a larger or

smaller ring of trees (Figure 8-91)

Figure 8-91

Continuing the discussion of painting and materials

from Chapter 8, this chapter focuses on using digital

photos to paint faces in your model, adding

photo-realism and saving modeling time

Using photos to paint faces can reduce the

num-ber of geometric elements you need to create

For example, you can take the time and effort to

model geometrically accurate windows on the

side of a building, or can you simply paint the

face with a photo of the side of that building (If

you don’t have an actual photo, a rendering works

well, too.)

In addition to saving modeling time, using

photos this way can greatly reduce file size For

this reason, Google encourages 3D Warehouse

contributors to use digital photos on their models

whenever possible Many of the models in the

3D Warehouse are photorealistic, as are many 3D

buildings in Google Earth Some of these models

represent extremely complex structures but are

modeled in simple geometry painted with photos

To see some examples, open Google Earth with

the 3D Buildings layer turned on, and explore any

large city Many buildings are plain gray, but a

large number are painted (For more information,

see Chapter 13.)

CHAPTER 9

Modeling with Digital Photos

This chapter covers all you need to know about painting with digital photos, including how to:Fit a

Use photos to make 2D components that

• look 3DEdit an imported photo

• Use photos to create 3D models

• Use Photo Match

•

Note

For the basics of where to find materials and images and how to get them into your model, see Recipes 8.1 and 8.2.

Positioning Textures with Free Pins

com-Note

The other positioning mode is Fixed Pins, which is used to

adjust the location, scale, and skew of a tiling material Fixed

Pins mode is demonstrated in Recipe 8.9

The main example demonstrates how to fit an image of

a door to a face In the “Other Uses” section, you’ll see

how fixed pins can fit images to the façade of a building

or to faces of a bureau

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Warehouse (Figure 9-1) A picture of a custom

garage door will be painted on the white face

Open the In Model folder of the Materials window,

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which contains the photo of the door Paint the

door photo onto the face (Figure 9-2)

The scale and location are not correct, and the

lower edge of the door in the photo is not

horizon-tal You will need to adjust the photo to fit within

the door face

Figure 9-1

Figure 9-2

Positioning Textures with Free Pins | 225

Right-click on the door and choose

ex-To place a pin accurately, you usually need to zoom

in very closely to find the correct points on the photo Using the Zoom window tool and the Previ-ous View tool can speed this process up immensely

In Figure 9-4, one pin was placed at each corner

of the rectangular part of the door, because these points are easy to find (It would be harder to place

a pin at the top of the arch.)

Note

When you lift and drop pins, look for dotted blue helper lines that indicate when a pin is horizontal or vertical from another pin.

Drag each pin to a corner of the door face in the

Figure 9-4

Figure 9-5

Figure 9-6

Use the Move tool to move the top edge of the door

8 Arc tool to trace the top of the door in the

photo Then use the Eraser to trim the rest of the

door face This results in a single door face with the

correct photo (Figure 9-8)

Figure 9-8

For a more realistic garage door, use Push/Pull to

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push in the door slightly The sides of the opening

will have the same material as the door, so repaint

them with the blue bricks (Figure 9-9)

Figure 9-9

Editing a Photo | 227

Other Uses

Free-pin positioning can be used for a multitude of models For example, Figure 9-10 began as a simple box model, and then each face was painted with a photo of

a building façade Compare the file size of this painted box (about 2.5MB because the graphic files themselves are large) with the 5MB size of an actual geometric model including all of those windows, doors, and orna-mentation Using graphics of smaller file size can keep your file size quite low

Figure 9-11 is a beautiful model of a Japanese bureau Each face is painted with a photo taken of a real piece of furniture

In the main example, you’ll see how to fix an image on a billboard In the “Other Uses” section, you’ll see how to make a change to a tiling stone image

Another method of touching up an image is described in

Recipe 9.3 With this method, you don’t edit the image itself;

you add new faces to “patch” the image.

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Ware-house (Figure 9-12) The antigraffiti billboard has

been defaced with, well, graffiti Also, the bottom of

the photo has some green leaves sticking out

Right-click on the billboard face and choose

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Texture→Edit Texture Image (In Windows, this

option is also available when you click on the image

thumbnail in the In Model folder of the Materials

window On the Mac, when you edit a material,

there is an icon for Edit Texture Image at the

bot-tom of the Edit Material window.)

The original photo used to make the billboard

opens in your default graphics editor (You can set

the default editor in the Applications page of the

Preferences window.)

Make the necessary changes to the photo Figure

3

9-13 shows the word Fun removed, and the

green-ery at the bottom trimmed above the billboard’s

The image in the In Model folder is updated as well,

but choosing Undo will bring back the original,

unchanged image The changes have not affected

the source graphic file, only the graphic internal to

the current SketchUp model

Figure 9-14

Adding Faces to Patch an Image | 229

Other Uses

You can also edit a tiled image Figure 9-15 shows two buildings with stone material Edit Texture Image is used to add a blue and red stone After you’ve saved the image and returned to SketchUp, the tiled image has been updated on all stone faces (Figure 9-16)

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Warehouse (Figure 9-17) This is a renovation nario, in which the windows on the wall indicated

sce-by the arrow will be removed and replaced with new windows

Figure 9-17

Draw a rectangle around the first window, as shown

Fixed or Free Pins In either mode, click and drag

the material itself (don’t drag a pin) slightly to the

left or right, so that the face contains only plain

bricks, keeping mortar lines aligned (Figure 9-19)

Figure 9-19

Right-click on the positioned material and choose

4

Done Now the material looks seamless, and the

window is removed, but you can still see the edges

of the new face (Figure 9-20)

Figure 9-20

If you erase these edges, the window in the photo

5

will return So hide the edges instead You can

se-lect the four edges, right-click on one of them, and

choose Hide from the pop-up menu, or you can use

the Eraser with the Ctrl/Option key pressed and

click all four edges Now you can’t tell there used to

be a window there (Figure 9-21)

Figure 9-21

Adding Faces to Patch an Image | 231

Repeat this patching technique for the remaining

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windows on the wall (Figure 9-22)

Insert new windows on this wall The windows

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shown in Figure 9-23 are available in the In Model folder of this model’s Components window This demonstrates one of the problems you can encoun-ter when using faces to patch an image: the wall is

no longer a single face, and the windows do not cut the wall properly

To fix the broken wall, first display the dashed lines

8

indicating hidden edges (View→Hidden Geometry) The dashed lines indicate the patching faces you added

Select the wall and all new windows, right-click on

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any selected face, and choose Intersect→Intersect Selected from the pop-up menu This creates intersection edges on all faces where they meet the windows Then you can erase the edges that fall within the new windows (Figure 9-24)

The patching method is a great quick fix for minor touch-ups, especially if you prefer not to edit your graphics But if the patched face might be changed afterward, such as getting new windows, editing the im-age in advance (Recipe 9.2) might prove less work than repairing a patched face

Figure 9-25

Position the material in each narrow rectangle to cover the logo Then hide the edges around each new rect-angle (Figure 9-26)

Figure 9-26

Using Images to Make Face Camera Components

Certain types of objects in your model can be represented by 2D images that give the “feel” of

a 3D object, because they always face you no mater how you orbit the model Good candidates are such objects as people, trees, plants, street lamps, trash bins—objects that look basically the same as you orbit around them (Figure 9-27)

In this example, you will create a Face Camera

compo-nent of a tree The tree image is an alpha-transparent

image, which means its background is transparent

(Recipe 8.12)

Note

Face Camera components are also sometimes called Face

Me components If you are searching the 3D Warehouse for

models like these, try both terms in your search.

Figure 9-27

Download my

3D Warehouse (Figure 9-28) The alpha-transparent

tree is painted on a vertical face next to the house

Note that the shadow of the tree is a rectangle;

SketchUp’s shadows do not recognize transparent

images

Figure 9-28

Orbit to a view like the one in Figure 9-29 The tree

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looks like a cardboard cutout at this angle Plus you

can see the face’s edges

Figure 9-29

Using Images to Make Face Camera Components | 233

To get more accurate

face to approximate the shape of the tree Use the Line or Arc tool to trace around the tree (Figure 9-30) Accuracy is not important for shadows, be-cause nobody notices the level of detail in a shadow, only its general shape When tracing, be sure to

look for the On Face inference Otherwise, you may

be drawing lines out of the plane of the face

Note

Because this image has a transparent background, you don’t have to trace around it exactly; the transparent background means that extra space around the leaves won’t be noticed If you were trimming around an image with a visible back- ground, you would want to trace the border more accurately,

so that no background would show If black edges are hard to see against the image, you can change the edge color in the Styles window (Edit tab, Edge page).

Use the Eraser tool to trim the corners of the

rect-4

angular face, so that only the tree shape remains (Figure 9-31) The shadow now looks tree-shaped.The next step is to hide the edges around the tree

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Activate Select and double-click the tree, which selects both the face and its edges Then press and hold the Shift key to deselect the face, leaving only the edges selected Right-click on an edge and choose Hide from the pop-up menu The tree looks quite natural (Figure 9-32)

Now the tree can be made into a component

Acti-6

vate the Select tool and double-click the tree, which selects both the face and its hidden edges Right-click on the tree and choose Make Component

In the Create Component window, select

Face Camera, make sure Replace Selection with Component is selected, but leave Shadows Face Sun off to ensure that the shadows appear properly Now you can insert more trees, which cast proper

Using Free Pins and a Single Image to Paint a 3D Object

If that one photo shows at least two faces of an object, you can use it to paint all faces that pear in the photo With this technique, you first paint and position the image to one face of the unpainted model If necessary, add or remove geometry to accommodate the picture Then you can use that positioned material as a basis for painting the remaining faces that are shown in the photo

ap-Two examples are used to demonstrate this technique In Example 1, you will paint a barn, and

in Example 2, a truck

Example 1: Barn with Free-Pin Positioning

In this example, you start with an unpainted box After

painting and positioning the front face, you will

com-plete the model geometry Then you will paint the rest

of the faces based on the material of the front face

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It is an unpainted box in the approximate shape of

a barn

Open the In Model folder of the Materials window

2

This folder contains the image with which the barn

will be painted The photo shows three faces: the

front, side, and roof of the barn Paint the image

onto the front face of the barn (Figure 9-34)

Note

This technique requires an unpainted model

to start If you want to create your model from scratch based on a photo, use Photo Match as described in Recipe 9.6 You can also use Photo Match on an unpainted model as explained in Recipe 9.7.

Figure 9-34

Using Free Pins and a Single Image to Paint a 3D Object | 235

Position this material by using free pins, placing

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one pin at each corner of the rectangular part of the barn’s front and dragging the pin to the corner of the model face (Figure 9-35)

Tweak the image if needed Then right-click on the

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image and choose Done The front face of the box is now painted with part of the front face of the barn (Figure 9-36)

To accommodate the rest of the front face, pull up

5

the top of the box until it reaches the top of the roof

in the photo Trace the outline of the roof on the front face (there are four edges) Then push back the corners of the front face, to complete the roof faces (Figure 9-37)

When tracing the roof, ideally the top of the roof

in the photo would meet the midpoint of the top edge, and the roof itself would be perfectly sym-metric But it’s hard to achieve that sort of accuracy with photos You can base your tracing entirely on the photo and get slightly inaccurate geometry, or you can create accurate geometry and use free pins

to tweak the photo so that it fits better It’s nearly impossible to get perfect results, but you can get pretty close (If accuracy is important, it’s ideal to start with a dimensionally accurate model on which

to paint Fitting the model to a photo works, too, but usually requires more steps and tweaking.)

be positioned

Figure 9-38