Focal length motion blur; keyframing focal point; help docs? Tweet

[scooternva]

1. I can't seem to get any motion blur when rapidly changing the focal length of the ThinLens camera in LightWave 2019.0.3 + OctaneRender 2019.1.4. For example, if I keyframe the focal length to rapidly zoom in on something from 28mm to 400mm in 10 frames, I should expect to see motion blur caused by the camera's rapid change in the focal length over such a short period of time. Is camera motion blur due to shifting the focal length not supported, or am I missing an obscure setting somewhere?
2. Focal depth is not keyframe-able in OctaneRender 2019.1.4. Can this be keyed in the current 2020.x versions with the Universal camera? I looked at the documentation for the standalone documentation and it wasn't clear whether this was a feature, and of course the LightWave plugin documentation is hopelessly out of date.
3. When is the LightWave plugin documentation going to be updated? It's now over four years and multiple versions obsolete.

Thanks...

[juanjgon]

Hi,

Some of the camera motion blur effects only can be rendered with F9/F10, so probably the problem is that you can't see the focal length motion blur in the IPR. Can you please check it out?

You can animate the focal depth parameter of the camera nodes (or any other parameter in the render target nodes) using the LW native constant nodes, as you can see in the attached image.

Hope it helps,
-Juanjo

[scooternva]

Oh, awesome! I completely missed that. I was simulating the effect by just physically moving the camera but that's not exactly the same thing of course.

Since you answered me so quickly and helped me out of a tight spot I won't mention that you didn't answer my question about the woefully out-of-date help documentation. Thanks Juanjgon!

[juanjgon]

Sorry, I don't have any ETA about the documentation updating yet.

Thanks,
-Juanjo

[scooternva]

OK, now I have a slightly different problem: I have a shallow depth of field in a scene I'm working on, and I want to manually rack focus (i.e., I'm not using autofocus). The ThinLens camera doesn't have an envelope on the "Focal Depth" setting (which is really focal distance) though, so there doesn't seem to be a way to keyframe the focus at various timings in the scene.

I know you showed a scalar node going into the Focal Depth input on ThinLens in the Render Target editor, but that's just a static value that stays the same for the entire scene. How would one go about keyframing focal distance? Thanks.

[tombosschaert]

Use a distance node from camera to a null?

[scooternva]

^^^ That's what I thought of too, but what do you plug into the "From" and "To" inputs on the Distance node? The Render Target editor (which is the context where you use the ThinLens node) sits above all of the other objects and items in a LightWave scene, so how would one go about getting the motion information for the camera and the "focus null" into the Render Target context?

ETA: Oh good grief, I feel like an idiot now. I sometimes forget that just because Octane can't access LightWave's instance information doesn't mean it can't access LightWave's ITEM information, which is a completely different thing:

Just remember to use world position for your camera and your focus null or you will get some... interesting results.