We need better options for "Propeller Blur" in IRAY
jdavison67
Posts: 650
in The Commons
In 3Delight you could do motion blur on spinning things...IRAY has no such solutions...
It's kindof a pain...I always have to fudge it in post, and it always looks...eh...bad.......
Just saying...
JD
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Comments
+1 & +2
Motion blur would indeed be nice, but I wouldn't hold my breath waiting for it.
Instead of postwork you might try some 'prework'. Quite a few (free) aircraft models (for instance from Neil Wilson or Pedro Caparros) come with blurred propellor(s) options. Usually that is just a primitive plane (no pun intended) with a blurred texture on it. What I do is make the prop on the plane invisible (depending on the model this may require some work with the geometrry-editor) and attach the primitve taken from the other model...and scale it to the right proportion, May take some liberties here and there as it may not always be possible to find a 'perfect' blurred prop (prop tip colours may vary) and of course one has to look for the right number of 'blades'
Just an example, blurred props done in 'prework'
https://www.daz3d.com/gallery/#images/963491
I recentley needed a propeller blur quite often during a comic project, that I canceled. However, I had a dirty work around for that problem.
Isolate your spinning prop from the rest of your scene. Make sure you have Dome OFF in your environment render setting. Choose a 1:1 aspect ratio for rendering.
Now take a side camera shot from your, let's say, wheel. Make it exactley match your render frame. Now render and save as png file. Take it to Photoshop and apply radial blur to it. Keep it, but make a black and white copy of it too. Maybe increase the contrast of the b/w version a bit. This is going to be your trans map. Your colored png will be your diffuse texture.
Back to DAT studio. Load a disc from the primitives and make it matching your wheel. Apply the textures, you've just created. Now it's trial and error to get the best proppeler blur effect. It might not be perfect, but it might do it.
This sounds promising....I may have to experiment...
JD
This sounds similar to what I do now....I find the perspective always seems a little off....
JD
Two work around options come to mind:
1. Create motion blur in 3DL with everything else hidden, render main scene in Iray and combine in postwork.
2. Blur Crazy which is currently 60% off, I've found this works best if you reduce the 'Cutout' value of the propeller, need to tweak the settings a few times to get the best results, see the attached picture for Blur Cray example, prop on top of the ballon is blurred this way.
Depends on the prop, but I have duplicated the item, rotated it and adjusted opacity map, rince, repeat a few times (usually about 7 or 8) and you get not too bad motion blur
For best results for prop blur in Iray . I use a flat pane created a rendered texture with the propeller and create a transmap for the opacity and replace the orginal propeller with the flat pane one using your texture map. Its easy to make. Simple to use and you can make it have a custom look to fit any propeller . I use it for airplanes, Helicopters, also the same trick works for the blur of the legs of a running horse etc.
I get results like the example in the animations. its cheating but for iray work around sometimes you need to find cheats. :) good luck
click to play animations
What is most odd is that Iray has a component for motion blur, you can find it in Iray's official documentation. And 3dsmax's Iray plugin has it since at least 2012, long before Daz ever got a plugin. So it is not like requesting a brand new feature, it is a feature that already exists! Just not in Daz. Why do we not have this much requested feature yet in 2020? What's the problem? What is holding it back?
Wind resistance.
Sorry, couldn't help myself, in a good mood as it's the first day of just over two weeks of holiday, heading off to the wilds of Norfolk (the UK county) for a week or so, first proper break since February.
The sad thing is, iRay seems to support motion blur since years. But for unknown reason Daz does not impment into the studio
As I understand it it is a new feature for DS, in effect as it would require changes to the render pipeline specific to that feature, with the consequent risk of breaking other features of the render pipeline. Obviously any such change needs to have the benefits weighed against the resources needed and risks incurred.
Has anyone experimented with Mesh Grabber Rotations for this kind of effect?
Then maybe the 'pipeline' could have a couple of user selectable valves (ie a checkbox with a defined action) linking to a parallel pipe so the user could be the one to determine if it works and decide not to use it if it doesn't. When no-one is able to use it means no-one can find if it works for them.
Oh, and DOCUMENT IT so people know risks & benefits.
..very nice.
For single frame images, I just use the prop blur discs that come with aeroplane models by Neil Wilson and Caparros and parent them to the aircraft..
There certainly may be several workarounds, but this is a devilishly difficult problem. If the goal of Iray is to simulate light acting on real objects, this is difficult. From different angles around a spinning prop, you get very different visuals. You get reflections off the prop surface as it's spinning, and those surfaces are curved. The other issue I see is, do you want this to look like it would be seen live by Human eyes, or look like a photograph taken at 1/1000th of a second? There's a big difference. With Human eyes, there's an effect related to a beat frequency where, depending on the speed of rotation, you see a slightly blurred image of the actual shape, and in between it's a lot more blurred. You can even see something like this appear to rotate backwards. Bottom line, I think asking a render engine to duplicate some or all of this is a bit much. Even something seemingly simple like a swinging sword has some of these problems.
Personally, I prefer pre-work solutions to post-work, because I'm terrible at real post-work! I like the idea of an object you can stick in a scene and fiddle with the opacity, but you won't get the reflections right that way.
Which aeroplane models would those be? I searched for Neil Wilson, Caparros, and Aeroplane but came up with nothing :(
Try on sharecg.com
AH! Thanks!
Or this link https://poserdazfreebies.miraheze.org/wiki/Aircraft for a list (and much more....)
I've read that Iray has code for motion blur, but DAZ hasn't implemented in DS yet. :(
https://www.nvidia.com/en-au/design-visualization/iray/features/ Most of the way down the page.
I Simulated prop blur on this Wright Flyer by using Blur Crazy.
1) Scaled the x axis of the propeller to widen it and then reduced opacity to about 12.5%
2) Loaded the Blur Crazy wheel, centered it over the propeller and expanded its diameter to the length of the propeller.
3) Applied The Rotary Blades material to the Blur Cray wheel and lowered the opacity.
Its not perfect but I think the result was acceptable.