View Full Version : Hello! Problem with Helicopter Blade Blurring

01-11-2007, 04:55 AM
I hope that someone out there can help me out with a
I have a model of a helicopter. What I can't seem to find is a way of showing the blades blurring as they rotate without using a huge amount of AA . I have searched the web and various forums for a tutorial about how to achieve this effect. I have seen a couple that talk about using a disc and placing an image of the blade blur onto it, but they don't go in to enough detail as to how this is done or show a pict of the image that should be used. Can anyone help?

Thank you


01-11-2007, 06:00 AM
Hi Wilfredo,
Had something of the same problem with the prop of a light aircraft. Solved it by working with the rotational speed of the prop and about 50% blur. Also had to throw in a couple extra blades to make it look right. The animation was of the engine starting, so had to sub my 4 blade prop for the normal 2 blade just as the engine fired. Turned out good, but took a long time.

01-11-2007, 06:08 AM

Thanks for this info. I notice that your plane animation was of the engine starting. My Helicopter will also be flying around so will the 50% blur not make the body of the helicopter too blurred?

I haven't tried adding extra blades (there are four already on this model), but it might work for me.

Thanks again


01-11-2007, 07:01 AM
Make the blades wider to span the full range of blur you want each blade to have and use segments along the width. Remember that the widening will be different along the radius of the rotor. Then apply a weightmap to drive opacity along the width, from centre to edge on each side. Reference this in a gradient on the opacity channel.

01-11-2007, 07:36 AM

Thanks. I'll try this right later on today, and get back to you. Maybe with a quick picture for you to look at.


01-13-2007, 03:09 AM
Hi Wilfrado,

One other approach you can try is to draw a circular prop disk, add inside it the desired number of blades, extrude it to give it some thickness for side-on views and texture it as required. Then do a screen print of it on a plane window background, import it into Photoshop (or equivalent) and add a motion blur effect - the blur effect is very quick to achieve and looks nice. Now you can use this as a texture for the original disk, adding transparency as required within LW. Its worked real well for me and then you do not have to use motion blur within LW if you don't want to; however, bear in mind that if you are going to have aircraft motion such as a flyby, you will need it but I found 25% seemed to work fine.

01-23-2007, 08:39 AM
A big thank you to all who replied to my post.

I have experimented with your suggestions, and have got what I was looking for.

Thanks again!