Change viewport "camera" and render to image file

gehairing · May 5, 2015, 4:41pm

Hi all,

I’m new to Rhino developping so my question is maybe stupid ;o)

From a C++ plugin i want to change the camera of a viewport to different orientations and render several images. By example : I want to turn the camera to the left, render an image, turn the camera up, render an image and so on.

I didn’t find how to do a “rendering” (from C++) to an image file (myImage.jpg by example).
If i use a “render” command it opens a window and i have no control over what happens.

I have serached in all samples and didn’t find something.

Can someone give me some directions to find out how to do this ?

Thanks :o)

dale · May 5, 2015, 6:34pm

Hi Georges,

First, here is the C++ samples repository - you may want to bookmark this.

When you say “turn the camera”, is there a particular Rhino command you are trying to emulate?

Until I hear back, here are a couple of samples that manipulate a view that you might want to take a look at:

cmdSamplePlaceCameraTarget.cpp
cmdSampleRotateView.cpp

Also, when you say “render”, do you want to run Rhino’s render command so the current render plug-in generates the image? If so, then just script the Render command using CRhinoApp::RunScript.

If you want to do something like Rhino’s ViewCaptureToFile command, then you might look at this sample:

cmdSampleViewCaptureToFile.cpp

Of course, more information as to what you want to do will be helpful…

gehairing · May 6, 2015, 4:44am

Hi Dale,

Thank you very much for your fast and detailed answer :o)
It seem’s to me that the samples you send here will answer my questions.

What i want/need to do is rendering (with current renderer) a camera that i turn in space.
For this i want to use the current renderer installed and selected by user.

The goal is to build a cubic panorama from 6 camera positions and export them in 6 square image files.
After that i have all the code (in C++) to build the panorama and user interface for viewing it.

gehairing · May 6, 2015, 1:45pm

Hi all,

After playing around with all this this morning i have something working but the result is not correct.

For the rendering i use the code below.
This gives me rendering of the current view for the moment so i can control the camera rotations.
Later i’ll have to use other rendering method because this one renders with a camera dependant lighting.
(i mean that the ligthing/shadows change when camera position changes)

// Render current view
bool CCommandIVisit::RenderCurrentView(int view, int resolution, CString folderPath)
{
    // Test command for rendering view port to a file :
    // _-ViewCaptureToFile C:\Users\Georges\Desktop\image1.jpg _Height=800 _Width=800 _enter

    // Prepare data
    WCHAR r[256];
    CString ifile = L"";
    ifile = folderPath + L"\\image";
    wsprintf(r, L"%d", view);
    ifile += r;
    ifile += ".jpg";
    wsprintf(r, L"%d", resolution);

    // Build the Rhino command
    CString cmd = L"!_-ViewCaptureToFile\n\"" + ifile + L"\"\n";
    cmd += L"_Width=";
    cmd += r;
    cmd += L"\n";
    cmd += L"_Height=";
    cmd += r;
    cmd += L"\n";
    cmd += L"_enter";

    // Run the command
    return RhinoApp().RunScript(cmd);
}

For the camera rotation i have tried out a lot of things but none is correct for me.
Here is the code i use (this is the most simple implementation i have found…doing the same as more complex camera position and target calculations).

void CCommandIVisit::RotateCamera(int view)
{
    ON_3dPoint direction;
    switch(view)
    {
        case 1: // Front
            direction = ON_3dPoint(-1,0,0);
            mFrontViewDirection = direction;
            break;
        case 2: // Left
            direction = ON_3dPoint(0,-1,0);
            break;
        case 3: // Back
            direction = ON_3dPoint(1,0,0);
            break;
        case 4: // Right
            direction = ON_3dPoint(0,1,0);
            break;
        case 5: // Up
            direction = ON_3dPoint(0,0,1);
            break;
        case 6: // Down
            direction = ON_3dPoint(0,0,-1);
            break;
        default:
            break;
    }
    RhinoApp().ActiveView()->ActiveViewport().SetCameraDirection(direction);
    RhinoApp().ActiveView()->Redraw();
}

The up and down views are not correct because i have to roll the camera to have a correct orientation.
I didn’t find out how to roll the camera.

Another problem i have is that i don’t know how to set the “field of view” correctly.
I need a FOV of 90° to have correct frames that i can assemble.
(i have tried SetCameraAngle with no success)

I have also tried the LeftRightRotate and UpDownRotate but these commands seem to rotate position and target of camera wich is not correct for what i need.

Maybe someone can tell me where i am wrong. Sorry if these questions seem a bit basic to you…i am total beginner in Rhino. (and also…english is not my native language as you have probably discovered )

Thanks a lot.

dale · May 6, 2015, 5:34pm

If you were to orient the camera just using Rhino command, how would you do it?

Knowing how you use Rhino will help me provide you with an SDK method.

Thanks,

– Dale

gehairing · May 8, 2015, 6:58am

Hi Dale,

Thanks for your answer.
I didn’t try any commands or scripting in Rhino because i prefer doing all code in C++.

What i want to do is the following:

allways keep camera position at the same place,
set field of view of the camera to 90°,
turn the camera (by moving only the target) to 6 different “targets”,
make a square image file (.jpg by example) from each of the 6 positions.

After this the 6 images are assembled to produce a cubic panorama.
That is why i need the 90° field of view.

The code i have done a few days ago is working partially (i pasted it above).
I have problems with the up and down view. I must “roll” the camera 90° left or right so that these views are correctly oriented. (edit : maybe “Roll” is called “Tilt” in Rhino…i have just looked at some camera code in Rhino scripting )
I have also problems to assemble the 6 views because i didn’t find how to set the field of view of the camera to 90°.

I’ll see if i can do things around this with commands and tell you if i find something. I use Rhino only for a few days now so i’m really not experienced

Georges

gehairing · May 8, 2015, 12:26pm

I have found that the following command give a view angle of 90°:

// Set the viewing angle
    CString cmd = L"_-PerspectiveAngle 45";
    RhinoApp().RunScript(cmd);

Can’t really remember how i have found this…and can’t explain why 45

gehairing · May 8, 2015, 3:02pm

I have finally found out a correct solution for all of my points above.
If my solution can help someone don’t hesitate to post/ask here for some sample code.

Thanks