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nigebabe
03-12-2007, 07:01 AM
Hi,

I am working on an aircraft model for my company and need to make the control surfaces move as close to the 'real' aircraft as possible. The aircraft has the normal ailerons but as it has short wings, it also uses spoilers to aid the effect of the aileron. For example, the port aileron has control limits of +17.5 and -14 degrees respectfully. The port spoiler has contol limits of 0 to +40 degrees. Therefore, the spoiler only moves upwards when the aileron moves upwards. I have set a control limit of 0 and +40 for the spoiler through the 'motion options' panel and have then applied a 'follower' to it to follow the aileron movement. This works fine until the aileron moves downwards and now so does the spoiler when it should remain at 0 until the aileron moves up again. How do I restrict the spoiler to upwards movement only? I am using LW 9.0 and have looked through the relativity options but I cannot seem to find something that works. Will it require an individual expression? I think it may but then I believe I am restricted to keyframing it via the graph editor rather be driven by the upwards movement of the aileron. (for complete accuracy, the spoiler actually only starts moving upwards when the aileron has reached +4 degrees and reaches its full travel when the aileron reaches +17.5 degrees)

Any pointers/solutions much appreciated.

Nigel

Bog
03-12-2007, 08:18 AM
I think you may be in need of an expression. I distinctly remember a "Clamp" operator therein which sounds like just the ticket.

Sounds like Follower doesn't respect Limits.

Phil
03-12-2007, 08:24 AM
Relativity: Supports limits per-channel, allows for references within a hierarchy (and also clone numbers, e.g Null (2)), also with conditionals and blends between motions. It's only irritation is the single line editing interface (I tend to resort to notepad or textedit when sketching out vaguely complex or lengthy expressions).

The description in your post suggests this wouldn't be tricky to automate via Relativity. Assuming you have LW 9

nigebabe
03-12-2007, 08:37 AM
Thanks for the prompt replies guys.

Phil, any chance you could expand on what you think the relativity expression may look like. I thought of blends but could not see how to do it. I think I need relativity and not a graph expression modifier?

Nigel

Phil
03-12-2007, 03:36 PM
Not today - overloaded with other stuff. I'll try and work something up based on your description during tomorrow.

j_j
03-12-2007, 11:09 PM
Using Relativity I put something together. Let me know if the movement is correct, not much of an aeronautics buff, I had to look up what a spoiler was.

nigebabe
03-13-2007, 05:27 AM
j_j,

Many thanks for taking the time and providing the zip and yes, it works perfectly. Hats off to you!!

I had a feeling it was something to do with blend but for me, the layout manual does not cover it particularly well. If they explained these kind of things with 'real-world' examples it would be much easier to appreciate and understand for mere mortals.

Thanks again.

j_j
03-13-2007, 12:48 PM
I agree about the manual. I had bought Prem's plugin Relativity prior to it being included with LW. I came with a step through lesson plan that took the user through each plugin. Newtek should consider making that available if it is not or make it easier to find if it is.

Surrealist.
03-13-2007, 01:05 PM
I agree about the manual. I had bought Prem's plugin Relativity prior to it being included with LW. I came with a step through lesson plan that took the user through each plugin. Newtek should consider making that available if it is not or make it easier to find if it is.

Any chance of you posting a link to this information or uploading a zip?

j_j
03-13-2007, 02:25 PM
I'll see if I can dig it up, and also check with Prem to make sure it is ok to release it. If the developer is ok with it than I'll post it.

Ztreem
03-13-2007, 03:07 PM
I know you have solved this with expressions, but I just want to say that things like this is easily done with cyclist.

Phil
03-13-2007, 11:56 PM
I've been waiting for an OK to upload the original Relativity documentation from either NewTek or Prem for around a year. I periodically nudge them, but to date neither has given me the nod.

No idea why Prem has vanished, but it's frustrating. NewTek, well, I don't know why the request has never been dealt with.