simple tracing - how to do?

simple tracing - how to do?

Post by Littleber » Sun, 06 Jul 2003 02:26:03



New to Gimp (also to the concetp of "layers").

What I want to do (as a learning aid) is to load
a picture of a volley ball (800X600X32 bmp), and then
create a black and white trace of it, showing the
indention lines you usually can see with a new volley ball.
This shouldn't be more than about 10 or so curved lines
in total.  But I want to be able to draw the lines ON TOP
of my photo of a volley ball so that they accurately
depict the outline of the ball and the indention lines.
Then I want to save my tracing as a black and white bmp
(or jpeg, I don't care).  I assume I need to load my
bmp image first, and then create a new layer (but I haven't
seen yet how to do that?????), and then use pencil or something
to draw the curved lines - how to do this?  This exercise
should be pretty simple, but, I am getting nowhere trying
to figure it out - any help?

Littleberry

 
 
 

simple tracing - how to do?

Post by Tom Harve » Sun, 06 Jul 2003 05:15:51


Try this:  right click on the image, select layers>layers, channels,
paths--- that will open the layers dialog box, in the lower left of that is
a new layer icon , click on that, adjust the opacity, draw away.  You
probably need to read the gimp help on working with layers, and "Grokking
the Gimp" on the same subject.
You might also want to experiment with this: on the original image right
click, image>colors>threshold.  By fooling with this you might be able to
have gimp draw the outline and indention lines on the volleyball.  Save as
new image to use that on top of other images etc.

Tom

Quote:> New to Gimp (also to the concetp of "layers").

> What I want to do (as a learning aid) is to load
> a picture of a volley ball (800X600X32 bmp), and then
> create a black and white trace of it, showing the
> indention lines you usually can see with a new volley ball.
> This shouldn't be more than about 10 or so curved lines
> in total.  But I want to be able to draw the lines ON TOP
> of my photo of a volley ball so that they accurately
> depict the outline of the ball and the indention lines.
> Then I want to save my tracing as a black and white bmp
> (or jpeg, I don't care).  I assume I need to load my
> bmp image first, and then create a new layer (but I haven't
> seen yet how to do that?????), and then use pencil or something
> to draw the curved lines - how to do this?  This exercise
> should be pretty simple, but, I am getting nowhere trying
> to figure it out - any help?

> Littleberry


 
 
 

simple tracing - how to do?

Post by Spamles » Sun, 06 Jul 2003 05:27:13



> New to Gimp (also to the concetp of "layers").

> What I want to do (as a learning aid) is to load
> a picture of a volley ball (800X600X32 bmp), and then
> create a black and white trace of it, showing the
> indention lines you usually can see with a new volley ball.
> This shouldn't be more than about 10 or so curved lines
> in total.  But I want to be able to draw the lines ON TOP
> of my photo of a volley ball so that they accurately
> depict the outline of the ball and the indention lines.
> Then I want to save my tracing as a black and white bmp
> (or jpeg, I don't care).  I assume I need to load my
> bmp image first, and then create a new layer (but I haven't
> seen yet how to do that?????), and then use pencil or something
> to draw the curved lines - how to do this?  This exercise
> should be pretty simple, but, I am getting nowhere trying
> to figure it out - any help?

Right click on the image.

Choose LAYERS|LAYERS_CHANNES_AND_PATHS

to bring up the layers toolbox if you don't
have it automatically shown.

Right click on the image again.

Choose IMAGE|ALPHA|ADD_ALPHA_CHANNEL

In the layers toolbox you should have one
layer, probably called "background".
Right click on it.

Choose DUPLICATE_LAYER

You now have two layers, the copy on top of
the original, the copy probably called
"Background copy"

You can work on either (even though you see
the top layer) by clicking on (selecting)
the layer in the layer toolbox.

Select (if it isn't) the top layer.

Now it depends on the image.

You may be able to get the edges simply
by using

right click on the image:
image|colours|brightness_contrast
and making it very bright with high contrast.
Then you would use, right click on the image,
select by colour, click on the white part
(assuming the lines you want are black)
and pressing CTRL-K to make transparent
everything except the lines.

There are other things you can do, such as
adding a transparent layer to the top, selecting
that, and using a draw tool manually to draw the
lines on the top layer over what you want on the
bottom layer.
(to do that, use the new layer option in the
layers toolbox and choose to create a new
layer which is transparent)

You could use the bezier tool to trace (on the
top, transparent layer. For a close curve that
is nice (smooth curves) and after drawing it,
click once inside it to select it (or use
the PATHS tab on the layers toolbox and
the path_to_selection option).

Then with the bezier selection chosen on the
top, transparent frame, use right_click,
EDIT|STROKE (you probably want to choose a
smaller size for the brush by clicking
on the large black dot on the main tool bar
which lets you choose the size).

When/if you get the traced lines on the
top layer you can do all sorts of things...
e.g. save the file (as xcf) if you want to
work on it later, then delete the bottom
(real image) layer and save the strokes
as a png file (which supports transparency,
now you have the outline on a transparent
background usable by anything that supports
png files, such as open office).

Does any of that help?

 
 
 

simple tracing - how to do?

Post by Phil Harp » Sun, 06 Jul 2003 08:40:23


to create a layer over the top right click on the image and go to
layer>layers, channels, paths

now click on one of the new layer icons at the bottom of the pallete
that should apear, now select transparent for the layer fill and click
ok, now you can paint over the top of the ball layer using a black pen
or pencil.

you could also try switching to the paths tab and drawing straight
lines on to the image, then bending them by clicking and dragging on
points.

you might like to read grokking the GIMP
http://gug.sunsite.dk/books.php(mirror) for the basics, or do some of
the tutorials on the GIMP.org site or GUG.

Hope that helps

Phil.


> New to Gimp (also to the concetp of "layers").

> What I want to do (as a learning aid) is to load
> a picture of a volley ball (800X600X32 bmp), and then
> create a black and white trace of it, showing the
> indention lines you usually can see with a new volley ball.
> This shouldn't be more than about 10 or so curved lines
> in total.  But I want to be able to draw the lines ON TOP
> of my photo of a volley ball so that they accurately
> depict the outline of the ball and the indention lines.
> Then I want to save my tracing as a black and white bmp
> (or jpeg, I don't care).  I assume I need to load my
> bmp image first, and then create a new layer (but I haven't
> seen yet how to do that?????), and then use pencil or something
> to draw the curved lines - how to do this?  This exercise
> should be pretty simple, but, I am getting nowhere trying
> to figure it out - any help?

> Littleberry

 
 
 

simple tracing - how to do?

Post by Littleber » Sun, 06 Jul 2003 10:54:14


Thanks for the input - yes, I see now how to create a new
layer - but I still can't get the drawing thing to go.
I don't want to use the edge mechanism because I really
want to learn how to draw - the book says there is this
thing called GFIG, but all it says is to "invoke GFIG",
but I do not see any button or option for INVOKE - so
I am stuck trying to figure that one out.  

As to bezier,
it does make a curve of sorts, and you can shape it,
but it just isn't intuitive like just letting me draw
a series of dots and then putting a smooth curve through
them.  And I can't seem to get bezier to finally stop -
if I select a different tool then all the work I did
goes away!  I am used to working with mspaint, and this
interface is very frustrating.  Why does it not give me
a full set of pixels to work with?  I ask for 800X600
and it only gives me about half that, and then it
clumsily creates partial lines - why?  I don't understand
this interface.  You start out with a giant screen divided
into two parts, and this initial screen seems to be quite
worthless - as soon as you start to do any work by selecting
a new drawing, all you get is a *y little overlay and
the big initial screens are just there like dummies.

How do you get GFIG?  How do you get a big canvas with
the exact number of pixels you ask for?  How do you get
the pixels you turn on (as with bezier) to TAKE (stay on
permanetnly)?  

If anyone can talk down at the mspaint level,
well maybe my experience with mspaint leaves me way too
primitive - I don't know.  The thing about mspaint is - it
would do what I want if it would allow for an option to draw
a curve connecting a series of dots and allow for bi-layers
so I could trace over a given bmp.  I am reading the GIMP manuals
(both the user's guide and the stoking), but they seem to
expect me to already be experienced with photoshop but I
have only useed mspaint.  

But thanks for the help - I'll keep struggling,

Littleberry

 
 
 

simple tracing - how to do?

Post by Spamles » Sun, 06 Jul 2003 12:46:54



> Thanks for the input - yes, I see now how to create a new
> layer - but I still can't get the drawing thing to go.
> I don't want to use the edge mechanism because I really
> want to learn how to draw - the book says there is this
> thing called GFIG, but all it says is to "invoke GFIG",
> but I do not see any button or option for INVOKE - so
> I am stuck trying to figure that one out.  

> As to bezier,
> it does make a curve of sorts, and you can shape it,
> but it just isn't intuitive like just letting me draw
> a series of dots and then putting a smooth curve through
> them.

You can draw a set of dots and lines between them.
Use either the pencil (on the main menu) or the
paintbruch (not the pen).

Click the first point. Move to the next.
Hold down shift and a line will appear.
Now click. You should choose the size brush
you want.

Besier is nicer! Smoothable. Remember, you can
adjust the tangent handles on the point separately
by holding down shift.

Quote:> And I can't seem to get bezier to finally stop -
> if I select a different tool then all the work I did
> goes away!

Bezier is for closed curves. Click on the starting point
to close the curve. Then click inside to select the region.
Then EDIT|TRACE to trace the curve. If, accidentally,
you click somewhere else and don't want to lose your
work (it has happened to me, too), on the layers toolbar
there is a PATHS tab. There may be several paths. Select
the one you were working on. At the bottom are icons.
One is to convert the path to a selection. If the path
is not closed, it will join the last point to the first
to close it.

Drawing on a transparent layer on top of the image lets
you ajust the Bezier curve quite accurately. If you have
a curve that is not closed, just close it up any old way
and later, after using EDIT|TRACE, just erase the part
you don't want.

Quote:> I am used to working with mspaint, and this
> interface is very frustrating.  Why does it not give me
> a full set of pixels to work with?  I ask for 800X600
> and it only gives me about half that, and then it
> clumsily creates partial lines - why?

Where did you ask for 800x600? The image can be 800x600
and displayed at a different size. You can use the equal
key to zoom in, the minus key to zoon out.
The "1" key to show it at the number of pixels you chose
(did you go through FILE|PREFERENCES on the main menu?).

Quote:> I don't understand
> this interface.  You start out with a giant screen divided
> into two parts, and this initial screen seems to be quite
> worthless - as soon as you start to do any work by selecting
> a new drawing, all you get is a *y little overlay and
> the big initial screens are just there like dummies.

What two parts? What giant screen? What size canvas?
Have you got it set for auto resizing?

You should have one screen and some toolbars (you can have
lots of separate toolbars), unless you open another image
in which case you get another image window.

Quote:> How do you get GFIG?  How do you get a big canvas with
> the exact number of pixels you ask for?  How do you get
> the pixels you turn on (as with bezier) to TAKE (stay on
> permanetnly)?  

Select an image window. Right click. FILTERS|RENDER|GFIG

This is a separate editor. It does not work on the image.
You create an image there, choose a scale (or scale to
the full image size) (the scale to image slidebar)
choose your brush size (the brush tab) and use the PAINT
button in GFIG. It will draw it onto the current layer.
It may be best to create a new transparent layer on top
and paint it on that so you can crop it, move it, etc.

To get an image of a given size,

Main tool menu:

FILE|NEW and choose the number of pixels.

You can show that at 1-1 sizing (press the "1" key)
or zoom in or out.

Quote:> If anyone can talk down at the mspaint level,
> well maybe my experience with mspaint leaves me way too
> primitive - I don't know.  The thing about mspaint is - it
> would do what I want if it would allow for an option to draw
> a curve connecting a series of dots and allow for bi-layers
> so I could trace over a given bmp.  I am reading the GIMP manuals
> (both the user's guide and the stoking), but they seem to
> expect me to already be experienced with photoshop but I
> have only useed mspaint.  

The GIMP interface is ... something it takes some work
to get familiar with (in the kindest terms).

It has freehand and line drawing tools and Bezier selection
(and you can use EDIT|TRACE to draw the Bezier curve once
 you have selected the Bezier region). You can have different
sized layers on top of layers on top of layers, some transparent,
some not ... you can create a very confusing collection of
layers which produce just what you want.

GIMP is powerful, but its interface is confusing.

Quote:> But thanks for the help - I'll keep struggling,

It will be a struggle for awhile. Once you can find the
tools (like GFIG) and know what they do, you can do a lot
with it.
 
 
 

simple tracing - how to do?

Post by Syni » Mon, 07 Jul 2003 09:46:50



> New to Gimp (also to the concetp of "layers").

> What I want to do (as a learning aid) is to load
> a picture of a volley ball (800X600X32 bmp), and then
> create a black and white trace of it, showing the
> indention lines you usually can see with a new volley ball.
> This shouldn't be more than about 10 or so curved lines
> in total.  But I want to be able to draw the lines ON TOP
> of my photo of a volley ball so that they accurately
> depict the outline of the ball and the indention lines.
> Then I want to save my tracing as a black and white bmp
> (or jpeg, I don't care).  I assume I need to load my
> bmp image first, and then create a new layer (but I haven't
> seen yet how to do that?????), and then use pencil or something
> to draw the curved lines - how to do this?  This exercise
> should be pretty simple, but, I am getting nowhere trying
> to figure it out - any help?

> Littleberry

Layers are cool once you figure out what they are.
Like, make a picture of a ball. Then click the
"new layer" button 9 times, and make them all
transparent.  Then replicate the balls on each
layer, moving up a bit, then down. When you save
it, save it as a gif. A prompt comes up and you save
it as an animation. Then you get to the prompt
that wants to know how you want to view the frames.
Be sure and change the default to 'replace'. and boom.
your animatin.  Works the same way with still images,
except you don't save as an animation. Of course, I
still suck.
http://personalpages.tds.net/~dcombs3/flower.gif

S

--
Let us support bi partisianship... I will hug your elephant, if you kiss
my ass.
http://personalpages.tds.net/~dcombs3 -the way it should be.

 
 
 

simple tracing - how to do?

Post by Phil Harp » Mon, 07 Jul 2003 10:22:14




> > Thanks for the input - yes, I see now how to create a new
> > layer - but I still can't get the drawing thing to go.
> > I don't want to use the edge mechanism because I really
> > want to learn how to draw - the book says there is this
> > thing called GFIG, but all it says is to "invoke GFIG",
> > but I do not see any button or option for INVOKE - so
> > I am stuck trying to figure that one out.  

> > As to bezier,
> > it does make a curve of sorts, and you can shape it,
> > but it just isn't intuitive like just letting me draw
> > a series of dots and then putting a smooth curve through
> > them.

> You can draw a set of dots and lines between them.
> Use either the pencil (on the main menu) or the
> paintbruch (not the pen).

> Click the first point. Move to the next.
> Hold down shift and a line will appear.
> Now click. You should choose the size brush
> you want.

> Besier is nicer! Smoothable. Remember, you can
> adjust the tangent handles on the point separately
> by holding down shift.

> > And I can't seem to get bezier to finally stop -
> > if I select a different tool then all the work I did
> > goes away!

> Bezier is for closed curves. Click on the starting point
> to close the curve. Then click inside to select the region.
> Then EDIT|TRACE to trace the curve. If, accidentally,
> you click somewhere else and don't want to lose your
> work (it has happened to me, too), on the layers toolbar
> there is a PATHS tab. There may be several paths. Select
> the one you were working on. At the bottom are icons.
> One is to convert the path to a selection. If the path
> is not closed, it will join the last point to the first
> to close it.

it's not only for closed cuves, if you're using the paths pallete
there's nothing to stop your stroking an open path, just select the
tool and brush you wish to use and click the ring icon, you don't have
to use a closed selection.

and if you want to stroke a selection that'd be <image> - edit -
Stroke

Quote:> Drawing on a transparent layer on top of the image lets
> you ajust the Bezier curve quite accurately. If you have
> a curve that is not closed, just close it up any old way
> and later, after using EDIT|TRACE, just erase the part
> you don't want.

just use multiple paths like layers

- Show quoted text -

Quote:> > I am used to working with mspaint, and this
> > interface is very frustrating.  Why does it not give me
> > a full set of pixels to work with?  I ask for 800X600
> > and it only gives me about half that, and then it
> > clumsily creates partial lines - why?

> Where did you ask for 800x600? The image can be 800x600
> and displayed at a different size. You can use the equal
> key to zoom in, the minus key to zoon out.
> The "1" key to show it at the number of pixels you chose
> (did you go through FILE|PREFERENCES on the main menu?).

> > I don't understand
> > this interface.  You start out with a giant screen divided
> > into two parts, and this initial screen seems to be quite
> > worthless - as soon as you start to do any work by selecting
> > a new drawing, all you get is a *y little overlay and
> > the big initial screens are just there like dummies.

> What two parts? What giant screen? What size canvas?
> Have you got it set for auto resizing?

> You should have one screen and some toolbars (you can have
> lots of separate toolbars), unless you open another image
> in which case you get another image window.

> > How do you get GFIG?  How do you get a big canvas with
> > the exact number of pixels you ask for?  How do you get
> > the pixels you turn on (as with bezier) to TAKE (stay on
> > permanetnly)?  

> Select an image window. Right click. FILTERS|RENDER|GFIG

> This is a separate editor. It does not work on the image.
> You create an image there, choose a scale (or scale to
> the full image size) (the scale to image slidebar)
> choose your brush size (the brush tab) and use the PAINT
> button in GFIG. It will draw it onto the current layer.
> It may be best to create a new transparent layer on top
> and paint it on that so you can crop it, move it, etc.

> To get an image of a given size,

> Main tool menu:

> FILE|NEW and choose the number of pixels.

> You can show that at 1-1 sizing (press the "1" key)
> or zoom in or out.

> > If anyone can talk down at the mspaint level,
> > well maybe my experience with mspaint leaves me way too
> > primitive - I don't know.  The thing about mspaint is - it
> > would do what I want if it would allow for an option to draw
> > a curve connecting a series of dots and allow for bi-layers
> > so I could trace over a given bmp.  I am reading the GIMP manuals
> > (both the user's guide and the stoking), but they seem to
> > expect me to already be experienced with photoshop but I
> > have only useed mspaint.  

> The GIMP interface is ... something it takes some work
> to get familiar with (in the kindest terms).

the GIMP interface is far superior to that of Photo$hop, no MDI to eat
up the screen. as for photoshop experience being required, most
photoshop users don't adjust well if compared to total beginnners,
maybe tuxpaint

Quote:> It has freehand and line drawing tools and Bezier selection
> (and you can use EDIT|TRACE to draw the Bezier curve once
>  you have selected the Bezier region). You can have different
> sized layers on top of layers on top of layers, some transparent,
> some not ... you can create a very confusing collection of
> layers which produce just what you want.

> GIMP is powerful, but its interface is confusing.

only if you're used to something else, and even then not necessarily

Quote:> > But thanks for the help - I'll keep struggling,

don't struggle, just read grokking the GIMP, http://www.veryComputer.com/
this is a kind of friendly RTFM request, don't jump into something
before you're learned the basics and complain that you can't do it, if
you don't want to learn anything in order to use the software maybe
http://www.veryComputer.com/;)

- Show quoted text -

Quote:> It will be a struggle for awhile. Once you can find the
> tools (like GFIG) and know what they do, you can do a lot
> with it.

 
 
 

1. Ray Tracings done at Apple

I was wondering if anybody knew how the Apple ray tracings were done. I know
that they used the Cray for most of the generations (some Mac II comparisons
were apparently done also), but I was wondering if it was all custom software,
and if there is any way that _any_ of the images or object files are available.

I do have some of the images, as many of those got out, but am looking more for
some of the object descriptions, as here at UCSC we have a roomful of little
used 386-based Xenix machines running U. Toronto's OPTIK program, that are
dying for me to diddle with them. I did do a few of my own descriptors, but
would like to see what parameters gave Apple the well known demo images.

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2. How would you do this? - px1.jpg (0/1)

3. It's done, done, done!

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