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Reference: Tutorials: Conversion 101 - Converting LDR Files to POV Files for Rendering

Conversion 101 - Converting LDR Files to POV Files for Rendering
By: Jeroen de Haan and Jake McKee
Posted: March 26, 2002
Version: v1 rev.1 110202

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Chapter 7: Taking the camera of the globe
The default Camera Globe position is nice for pictures of the outside of a model. But what if you want a picture from within a model, almost as though you were inside the model looking out? You could change the radius to very small negative number so the camera will be in the model but the outcome will be very unpredictable. Therefore, it is better to take the camera from the globe so to speak and give it a fixed location. Instead of using the Camera Globe Position, we are going to use the Camera Coordinates in this chapter.

To get started, we need two coordinates: the camera coordinate and a "look at" point: the point where the camera will look at (or point at). These coordinates are LDraw coordinates so it is easy to determinate these.

Open the CAR.DAT in your LDraw editor (because I use and know MLCad best I will use that in this example but any other editor will do).

Place a 1 x 1 Brick inside the car above the chair at a height of a minifig's head. Make a note of the coordinates, which we will call -cc (it will be something like 0, -72, 10). Now place a 1 x 1 Brick in front of the car approximately at the same height as the one inside the car. You can place it a bit lower than the one inside, but don't over do it. Make a note of the coordinates, which we will call -cla (it will be something like 0, -56, -310). Delete both 1 x 1 Bricks and close the editor, without saving CAR.DAT.

Open L3PAO and open the CAR.DAT. Add a floor and background. Select the Camera Coordinates box (-cc), and fill in the coordinates in the three fields. Now select the Camera Look At box (-cla) and fill in the coordinates in the three fields. Change the output name to CARCC.DAT. Click "Run L3P" and open the .POV file.

After rendering, it will look like this.

Now you know what a mini-fig would see when driving a car! You can see the steering wheel and the reflection of the drivers seat in the window. You will have noticed that the time it took to render was considerable longer than the other pictures. This is because POV-Ray had to render through the windscreen and has to calculate all the refractions and reflections.

Now let's do this again, but from the outside to the inside of the car, like a car promotion brochure.

Open the CAR.DAT again in an LDraw editor. Select the steering wheel and make a note of its coordinates (0, -16, -30) , which will be the Look At coordinates (-cla).

Place a 1 x 1 Brick outside the car at the height of the roof and by the door. Make a note its coordinates (80, -80, 20), which will be the Camera Coordinates (-cc).

Now close the editor (again, don't save) and open L3PAO. Open the car, fill in the coordinates in the right fields. Choose 45 as camera angle (-ca). Select a floor and a blue background. Change the output file to CARCC2.POV.

Before you run L3P, we are going to save all these options in a "Scene".

Open the File menu and click "Save Scene". A standard Save as... window opens with L3P as directory (don't change that!). Now save the scene as CARCC2.xxx. If you were to close L3P (don't, but let's say) and want to use the same settings/options, all you have to do is open a DAT/LDR file, select "Open Scene" from the File menu and you are ready to go! No need to write everything down!

Hit "Run L3P", exit L3PAO and open CARCC2.POV in POV-Ray. Hit the "Run" button and wait...

The above image is the result. Because the rotation point of the Steering Wheel is at the bottom of the part, we are looking at the bottom of the car, or in other words: the center of the picture is not the steering wheel.

The good news is, is that we saved the options (phew!) and don't have to open the car in an editor to determine the coordinates.

Open L3PAO, load CAR.DAT and choose "Open Scene" from the File menu. Open the CARCC2.xxx. You see that all the parameters you used last time are back! Now all you have to do is to change the Y coordinate of the Look At point. Let's try two plate heights (or 32 LDraw units). So change the -16 in the second Look At box to -32.

Change the output name to CARCC3.POV, hit "Run L3P", exit L3PAO and open CARCC3.POV in POV-Ray. Hit the "Run" button and wait again while the image renders.

Yes, that is much better! The steering wheel is more in the center of the picture now.

Tips

  1. Start working out the Camera Globe position. Use the "car in the globe" picture to determine the position of the camera. Start with simple models first.
  2. Use the camera angle creatively but with care: use normal or tele-lenses (<50 degrees) for model presentation. Use a wider lens (>60 degrees) to add dynamics to a model or scene or to make it more "dramatic".
  3. Creation should be 90% Inspiration and 10% Transpiration. Look at real life pictures of objects similar to your model: how did other photographers take their picture? What was their point of view: low (or frog-view), normal viewing height or from a higher point (birds eye). Or think mini-fig height. Use a mini-fig to determine the camera coordinates.

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