Irrlicht Engine

sorry.....I still do not get it....
Could you please give me some sample code?

If I click on the GUI element (not root), it will be focused.

That means EGET_ELEMENT_FOCUSED will be checked.
But....by clicking the GUI element, that means EMIE_LMOUSE_PRESSED_DOWN will also be checked.

How to ...

With env->getRootGUIElement()->getElementFromPoint
you can check which element is below the mouse. If it is anything but the RootGUIElement itself then you are probably over a gui-element and don't want to handle those mouse-events for 3D selection.
How to check if env->getRootGUIElement ...

how to ignore the things in the background when the GUI element is focused?

case EGET_ELEMENT_FOCUSED:
{
//what to do?
}break;

Also, if the element is focused, that means the user clicks the left mouse button on the element meaning that EMIE_LMOUSE_PRESSED_DOWN is also triggered.

How to ...

Also, another problem is that if I click on the GUI element, the object in the scene (at the back) will be selected.

How to solve that

hybrid wrote:You can either switch to modes (i.e. when GUI is open don't set rotate) or check if a GUI element has focus and send the event there.

How can I check if the GUI element is focused?
Which API should be used?

guielement -> isEnabled()?

http://img.photobucket.com/albums/v252/wongsiwai/ScreenHunter_08Mar292022.jpg

My program has an operating mode called MODE_ROTATE to rotate objects. This operating mode is triggered when the user presses 'r' key.

Now, the problem is, as you can see in the above picture, the user would like to ...

how to apply the skin to the IGUIButton?

Can I add a border with a certain thickness around the button when it is clicked using Irrlicht?

Yes, better choice.
This code draw rectangle, sorry for python

device = createDevice(EDT_OPENGL, dimension2du(640, 480))
driver = device.getVideoDriver()
smgr = device.getSceneManager()
camera = smgr.addCameraSceneNodeFPS()
camera.setPosition(vector3df(50,200,50))
m = SMaterial()
m.Lighting ...

The cubeNode buttom has y-value 0 by default.

Now, what I want to do is set the height to a certain value, say 100, then the cube should be of height 100 with its bottom y-value unchanged (i.e. still be 0)

How to solve that?

But how are the lines drawn? How to represent the rectangle? Which API should be used?

IVideoDriver->draw3DLine(vector3d<f32> start, vector3d<f32> end) see my link above

IVideoDriver->draw2DRectangle(SColor, rect<s32>(X1, Y1, X2, Y2))
from 2DGraphics example 6

Would draw3DBox() be better ...

You can use ISceneCollisionManager ::getRayFromScreenCoordinates to create a ray which you can then collide against a plane to get a point in 3D. The plane basically sets the height at which you want that ray to collide so in your case it will probably have normal vector pointing upwards and a d ...

The rectangle in the above picture is in XY plane.
How can I change it to XZ plane when the user drags and drops the mouse?

I am wondering if Irrlicht engine can handle the case in which the user clicks the left-mouse button and drags and drops to create a rectangular selection.

For example,
http://img.photobucket.com/albums/v252/wongsiwai/ScreenHunter_01Mar011654.jpg

My question is how I can draw this rectangular ...

well turbosquid is one of the biggest.

i think this one you know:

http://www.3dmodelfree.com/3dmodel/list468-1.htm

btw you also could convert 3d models to another file format or import them into free tools.

Anyway usualy someone who has the money to buy 3DS max should be able to pay a price for ...