Go Back   Knife Edge > RealFlight - Designer's Corner > RF-X - Designer's Corner
Use of this site is subject to our Terms of Use. | Technical Support is available from Great Planes Software Support.

Reply
 
Thread Tools Rate Thread Display Modes
  #16  
Old 02-12-2018, 11:06 AM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by asj5547 View Post
If I set rolling resistance down to 20% it is difficult to make aircraft stick, 30% sticks often.
Only way to make T-28 not stick when applying gentle throttle is to set rolling resistance multiplier 1% and friction multiplier 50% (minimum settings) for the FRONT WHEEL only, leave main wheels at 100%
I just tried this in RF-X

Rolling Resistance 10%
Friction Multiplier 50%

On the Medowlands RC Field when the plane is loaded it starts rolling forward and keeps going off the runway and all the way across the field until it hits something and makes the break apart sound, the plane is hidden in the foliage by that time. What does it do for you there?
Reply With Quote
  #17  
Old 02-12-2018, 04:38 PM
asj5547 asj5547 is online now
Registered User
 
Join Date: Aug 2017
Posts: 736
Quote:
Originally Posted by technoid View Post
I just tried this in RF-X

Rolling Resistance 10%
Friction Multiplier 50%

On the Medowlands RC Field when the plane is loaded it starts rolling forward and keeps going off the runway and all the way across the field until it hits something and makes the break apart sound, the plane is hidden in the foliage by that time. What does it do for you there?
When plane loads in Meadowlands it just sits there until I apply the absolute minimum amount of throttle to start it rolling (no sticking)
and because it is a down hill slope, it just keeps rolling until I apply down elevator for brakes and I can stop the T-28 on the runway. Yes it will roll all the way if I let it.
Talking of brakes, can you give the brakes a little more stopping power, I have tried altering the brakes graph points in the editor, but the editor does not save them.!
My rolling resistance is set to only 1% and 50% friction.
Reply With Quote
  #18  
Old 02-12-2018, 07:48 PM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by asj5547 View Post
When plane loads in Meadowlands it just sits there until I apply the absolute minimum amount of throttle to start it rolling (no sticking)
and because it is a down hill slope, it just keeps rolling until I apply down elevator for brakes and I can stop the T-28 on the runway. Yes it will roll all the way if I let it.
Talking of brakes, can you give the brakes a little more stopping power, I have tried altering the brakes graph points in the editor, but the editor does not save them.!
My rolling resistance is set to only 1% and 50% friction.
Thanks. When my plane loads it starts rolling right away, no throttle needed. And yeah it needs a tad more braking power I've been meaning to add some but I keep forgetting .. thanks for reminding me.
Reply With Quote
  #19  
Old 02-12-2018, 09:32 PM
asj5547 asj5547 is online now
Registered User
 
Join Date: Aug 2017
Posts: 736
Quote:
Originally Posted by technoid View Post
Thanks. When my plane loads it starts rolling right away, no throttle needed. And yeah it needs a tad more braking power I've been meaning to add some but I keep forgetting .. thanks for reminding me.
I have the T-28C in my hanger now, thanks for the download, that 9 cylinder radial looks great and the plane fly's perfect. (already removed the glue from the front wheel)
Lets hope Jeremy's high poly count fix will solve this problem for you.
Now back to flying, and looking for something I can get that tailhook latched onto!!! there must be a phone line around somewhere.
Reply With Quote
  #20  
Old 02-12-2018, 09:42 PM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by asj5547 View Post
I have the T-28C in my hanger now, thanks for the download, that 9 cylinder radial looks great and the plane fly's perfect. (already removed the glue from the front wheel)
Lets hope Jeremy's high poly count fix will solve this problem for you.
Now back to flying, and looking for something I can get that tailhook latched onto!!! there must be a phone line around somewhere.
Cool I'm glad you like it. Now where is that telephone line

I have the tire collision mesh up to 196 triangles now. The mesh is curved a little across the top just like the tire and has four sections just like tread would be. But I'm beyond the 1,500 triangle limit so I have to remove some more triangles somewhere before I can test it. Right now I'm watching a movie with the wife so no work until later. Just put on a pizza so I better check it.
Reply With Quote
  #21  
Old 02-12-2018, 09:50 PM
abaser's Avatar
abaser abaser is offline
Registered User
 
Join Date: Jun 2010
Location: stuttgart, AR
Posts: 4,442
For wheel C meshes, I'll usually take the center row of polys of the wheel and duplicate them. I'll then cap the sides and scale the width to match the width of the tire. I don't try to match the curvature of the tread because you'll never notice that it's off in the sim. To be honest, I've got a few models up that don't even have a collision mesh at all and I can't tell any ill affects from it. They were my earlier models so the newer RF versions may reflect otherwise.
Reply With Quote
  #22  
Old 02-12-2018, 11:25 PM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by abaser View Post
For wheel C meshes, I'll usually take the center row of polys of the wheel and duplicate them. I'll then cap the sides and scale the width to match the width of the tire. I don't try to match the curvature of the tread because you'll never notice that it's off in the sim. To be honest, I've got a few models up that don't even have a collision mesh at all and I can't tell any ill affects from it. They were my earlier models so the newer RF versions may reflect otherwise.
None of my older models had a collision mesh, RF 7.5 or RF-8 doesn't require it. But RF-X does and the first plane I tried without a collision mesh got terrible frame rates until I added a collision mesh for it. That's a pretty good idea of duplicating the center two polys and capping it, but it seems what I did will work the same. I didn't curve the c. mesh because I thought it needed it I just did it to make it more like the real tire since I was adding so many triangles to it. I checked two of the Planes that's built into RF-X and one had 220 triangles and the other had 240 triangles for the collision mesh for all of the tires. And since you can't see what the c. mesh looks like I just curved it to mimic the tire not knowing what they did.

So a question. Does the collision mesh act as a solid part in the graphics engine, or is it a mesh so it has holes for something to stick through? Like the tire getting stuck in RF-X and the plane won't move. Then if the mesh is closer (more triangles) the tire doesn't get stuck because the holes are smaller and what's on the surface doesn't stick into the mesh and cause it to stick.
Reply With Quote
  #23  
Old 02-13-2018, 12:17 AM
Bill Stuntz's Avatar
Bill Stuntz Bill Stuntz is offline
Registered User
 
Join Date: Dec 2000
Location: Columbus, OH USA
Posts: 390
Send a message via ICQ to Bill Stuntz
Probably a stupid question/suggestion since I'm not a builder:
Is the collision mesh aerodynamically/physically significant? For instance, is it the tire that actually rolls the ground? Or does the collision mesh lift the tire off the ground? If it's the mesh, would making the mesh slightly smaller than the tire allow the rounder tire to contact the ground & roll more smoothly?
Reply With Quote
  #24  
Old 02-13-2018, 01:33 AM
abaser's Avatar
abaser abaser is offline
Registered User
 
Join Date: Jun 2010
Location: stuttgart, AR
Posts: 4,442
The collision mesh is just as it sounds. It's a shell put in place over the visual model to define the contact points of the mesh it's assigned to. Take my Toucan for example. The tail breaks off when you nose it in the ground. This happens because I extended a point of the collision mesh out in front of the spinner.

With wheels, you want to match the diameter as close to the tire itself because that's what controls the impact of the tire. If your Cmesh is square, your round wheel will roll as if it's a cube and bounce all over the place. Want to see something really fun? have the Cmesh pivot reversed. Your wheel will look as if it's rolling backwards.
Reply With Quote
  #25  
Old 02-13-2018, 02:00 AM
Bill Stuntz's Avatar
Bill Stuntz Bill Stuntz is offline
Registered User
 
Join Date: Dec 2000
Location: Columbus, OH USA
Posts: 390
Send a message via ICQ to Bill Stuntz
Thank you for the explanation. That's about what I thought, but I wasn't sure.

Am I correct in assuming that the collision mesh is not involved aerodynamically?

Since a collision mesh apparently isn't required except in RF-X, what happens when an aircraft doesn't have one? Does it just remain intact in a crash? How do I know whether an aircraft does or doesn't have a collision mesh? Why would the lack of one decrease the frame rate in RF-X? More contact points to calculate in the more detailed structure? At least I assume that the structure is more detailed than the collision mesh. Does the collision mesh simplify the calculations?
Reply With Quote
  #26  
Old 02-13-2018, 02:01 AM
adrenoline 60 adrenoline 60 is offline
Registered User
 
Join Date: Jan 2014
Location: Wisconsin
Posts: 643
Quote:
Originally Posted by abaser View Post
Want to see something really fun? have the Cmesh pivot reversed. Your wheel will look as if it's rolling backwards.
Iv seen that. Another mystery solved.
Reply With Quote
  #27  
Old 02-13-2018, 09:07 AM
abaser's Avatar
abaser abaser is offline
Registered User
 
Join Date: Jun 2010
Location: stuttgart, AR
Posts: 4,442
Quote:
Originally Posted by Bill Stuntz View Post
Thank you for the explanation. That's about what I thought, but I wasn't sure.

Am I correct in assuming that the collision mesh is not involved aerodynamically?

Since a collision mesh apparently isn't required except in RF-X, what happens when an aircraft doesn't have one? Does it just remain intact in a crash? How do I know whether an aircraft does or doesn't have a collision mesh? Why would the lack of one decrease the frame rate in RF-X? More contact points to calculate in the more detailed structure? At least I assume that the structure is more detailed than the collision mesh. Does the collision mesh simplify the calculations?
I'll try to answer what I know.

Aerodynamics is set in the editor and controlled by the parameters set there. So the Cmesh has nothing to do with that.

Usually, if the model doesn't have one there's no ill effects other than parts may sink into the ground after a crash. That can be interesting to watch.

The model can still break apart on impact if there isn't a Cmesh. The only thing a Cmesh affects is telling RF where to make contact with the model.

And yes, the Cmesh is far less detailed than the visuals. You have a 1500 poly limit for all of the collision meshes combined. I've got that much in my tail gear on my Citabria.
Reply With Quote
  #28  
Old 02-13-2018, 01:03 PM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by asj5547 View Post
I have the T-28C in my hanger now, thanks for the download, that 9 cylinder radial looks great and the plane fly's perfect. (already removed the glue from the front wheel)
Lets hope Jeremy's high poly count fix will solve this problem for you.
Now back to flying, and looking for something I can get that tailhook latched onto!!! there must be a phone line around somewhere.
asj5547

Here's a new beta for you to try out. The first pass of increasing the triangle count of all the tires collision mesh really didn't seem to help, some maybe but not much. But Jeremy said they had problems when the poly count was too low so I went back and added an angle cut for all the segments in the collision mesh and also made the nose tire 1 inch wide instead of .82 inch wide. Adding the cross cut to all the segments doubled the poly count while leaving the triangle count the same, and it seemed to help quite a bit to me. It's still not perfect but the sticks seem to be way down and a short burst of the throttle seems to unstick it. So if you would please give this a try on several airports and let me know what you think. Thanks for your help on this.

Beta with improved collision mesh for all tires and nose tire is wider. Oh I upped the braking some to 90% on the main gear and 5% on the nose gear. The nose gear didn't have any braking and the main gear was 80%. I also uploaded pictures of the 1st way I did the improved collision mesh and a 2nd picture of how I added the extra poly in each segment. That's the way the tires are too.
Attached Images
File Type: jpg T-28C Trojan 14.jpg (109.4 KB, 1 views)
File Type: jpg T-28C Trojan 15.jpg (95.3 KB, 2 views)
Attached Files
File Type: rfx T-28C Trojan_EA.RFX (3.26 MB, 8 views)
Reply With Quote
  #29  
Old 02-13-2018, 01:39 PM
abaser's Avatar
abaser abaser is offline
Registered User
 
Join Date: Jun 2010
Location: stuttgart, AR
Posts: 4,442
RF automatically triangulates your 4 sided polys so what you did didn't do anything for the poly count as far as RF sees it. At least that's the way it used to be. If RFX has a problem with what you show then it's something they need to take care of on their end. None of my wheel meshes are that detailed or high poly and I've never seen an issue.
Reply With Quote
  #30  
Old 02-13-2018, 01:51 PM
technoid's Avatar
technoid technoid is offline
Registered User
 
Join Date: Oct 2014
Location: Texas
Posts: 6,029
Quote:
Originally Posted by abaser View Post
RF automatically triangulates your 4 sided polys so what you did didn't do anything for the poly count as far as RF sees it. At least that's the way it used to be. If RFX has a problem with what you show then it's something they need to take care of on their end. None of my wheel meshes are that detailed or high poly and I've never seen an issue.
I know about the triangulate deal but what I did made a major difference in RF-X so it did something. I'm just trying to do anything I can to make the plane better in RF-X before I release it. And yeah, all the cmesh for tires I've done in the past is very simple compared to this.. but that was for RF 7.5. Anyway what I did made a major change in RF-X for me and I'd be able to go with what I've done to improve it in RF-X and feel people could fly the plane okay. But before the sticks were terrible. But right now I'm waiting to see how it works for asj5547 before I go with it. I don't want to lower the rolling resistance way down it caused the plane to roll as soon as it loaded for me.
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:06 AM.