I’ve put together a little model to help people visualize and set up camera placement to match their Octane and Blender models. This should hopefully also work for other modeling packages that can import OBJ files. This is for anyone who wants exact camera placement without having to know trigonometry.
Included in the zip file are Blender, OCS, OBJ and Mtl files.
As Blender units are meters, it matches in the OctaneAxis.ocs and OctaneAxis.blend files.
The Axes is where differences come in. Note that when translating between Octane's Z and Blender's Y the sign is flipped.
The following table shows how coordinates match:
Octane | Blender
X = X
Y = Z
Z = Y *-1
Image size as presented here is 1280x960 for both programs. Octane's FOV is 45 and approximates to Blender's Lens at 39.
If you extract all the files to D:\Octane\OctaneAxis, you should be able to open the OctaneAxis.ocs file in Octane without any problems. For a different directory, you'll have to edit the OBJ, OCS, and MTL files. If you only have the demo version, you’ll have to open the OBJ file.
Lets begin.
1. Click on the Preview Camera icon to bring up the “Mesh Preview Camera”. Click on the Expand All nodes button.
2. The “target” node should be 0,0,0 (viz. x,y,z). This is the rotation pivot of the whole scene. It is located at the center of the red sphere. In the Blender file, this is the intersection of the x,y, and z axis.
3. The “pos” node is where the camera is located and will always point toward the “target node”. This is why when you try to zoom and zoom and zoom, things come to a stand still. You can't get to an object beyond the "Target" position. The object you want to get to needs to become the new "target position" a spot before the target position. This will be demonstrated further on.
4. Zoom out with the middle mouse scroll button till you get a good view of the scene. Then hold down the left mouse button and move the mouse around. You’ll notice that everything pivots around the red sphere. If it doesn't, make sure that the "target node" is set to 0,0,0.
4. Now lets pivot around the 20 meter mark on the X-axis. To do this, enter 20 into the field for the X-axis in the “target” node. Move the mouse around. Notice that everything moves around the model's 20 meter X-axis mark.
5. Now try another spot like -40 meter Z-axis. In Blender, this corresponds to +40 Y-axis of Blender's grid (not the model's Y-axis). So, in Octane's field for the z-axis enter -40 and change the x and y axes to 0. Move the mouse and see how things work.
6. Now set the "target" node back to 0,0,0.
7. Lets move the camera to +40 z-axis. Enter 0 into the x-axis, 20 into the y-axis(height) and 40 into the z-axis. I think due to a bug in the program, the first time you do this and then move the mouse with the left mouse button, it reverts to a previous setting. But go ahead now and enter 0, 20, and 40 again. This time, use the mouse scroll wheel to zoom out. The word North should be at the top of the screen.
To set the same camera position in Blender, enter 0 in Loc X, -40 in Loc Y and 20 in Loc Z.
Now in Octane, zoom in to within a few meters of the red sphere.
8. Change the “target” node to -40 x, 0 y, 0 z and scroll the mouse wheel. You should see the -40m object at the same distance as you left off from the sphere. Zoom out a little and move the mouse around. You should see the word “West” close by. Do this exercise a few times and you'll understand how to place a camera anywhere within a large scene.
Now lets see how to match a camera position in Blender with Octane.
1. Open up OctaneAxis.blend. If the “Transform Properties” form isn’t up, Press N. Move the camera to a spot that you’d like to match in Octane.
2. Initially, just enter these values in the “Transform Properties” box to begin with. Enter the following Loc X: 40, Loc Y: 0, Loc Z: 20.
3. In Octane, Enter 0,0,0 in the “Target node” and 40, 20, 0 in the “Pos” node. Octane's X matches Blender’s “Transform Properties” Loc X, Octane Y matches Blender Z and Octane Z matches Blender Y *-1. The modeled axes are setup to match Octane's orientation for OBJ files exported from Blender.
In Blender, the camera has a constraint on the red sphere. In Octane, the camera always points at the camera's "target" position. If you move the red sphere in Blender, the camera will follow it. Move it to a position corresponding to a view you'd like to see in Octane. Change Octanes's "target" coordinates to match the coordinates of the red sphere. The views should more or less match.
There you have it, the camera positions now match in Blender and Octane.
Please note, if you set Octane’s "Target" node, it’ll remain intact as long as you don’t pan the scene using the right mouse button. Panning changes the "Target" location.
Summary
So how do you match a camera in Blender and Octane?
1. Click on the object that will be the target of your render.
2. Press N to bring up the "Transform Properties" form.
3. Move its “Transform Properties” (Loc X, Y, Z) settings to Octane’s corresponding "Target" settings, X to x, Y to -Z or -Y to Z, Z to Y.
4. Move the camera to a position pointing to the object of interest and convert its Loc X, Y, and Z settings to Octane’s "Pos" settings.
That's it! A visual tool to set up your camera in your modeling program to match Octane. Happy Octaning!
BroAugustine
OctaneAxis.zip- (562.81 KiB) Downloaded 409 times
