Atomic Systems

M&GN Class A - How to get rid of bugs?

Well, here is the model; an M&GN Class A with early boiler. Not 100% complete, but near as dammit...







...and now for the bugs bit. As you may have seen in some of the pictures; the model does not to have a front bogie. However, this seems only to be a trick within the program; as you zoom around the model, the bogie appears and dissapears randomly; see below.





Can anyone help with this problem? I believe it is a mip or mapping problem, but not having had this problem before; I can't say.

I love those ancient 4-4-0s. Very elegant.

I had the same problem a couple of years ago with brake shoes that would disappear whenever the camera was rotated into the rear 180 degree arc of the loco.

If I remember correctly it was either an alpha sorting issue or the order that I had the brake shoe object linked to the bogie. The brake shoes where a separate object that had an alpha texture applied to it. The bogie it was linked to also had the same alpha texture applied to it.

Sorry I can’t recall exactly what the cause was but I am pretty certain it was not related to MIP mapping or texture mapping.

superheatedsteam wrote:I had the same problem a couple of years ago with brake shoes that would disappear whenever the camera was rotated into the rear 180 degree arc of the loco.

If I remember correctly it was either an alpha sorting issue or the order that I had the brake shoe object linked to the bogie. The brake shoes where a separate object that had an alpha texture applied to it. The bogie it was linked to also had the same alpha texture applied to it.

That's exactly the problem; I'll have a go with the alpha layering and exporting. It might be to do with the alpha layers of the frames interfering with the bogie's textures. Thanks very much!

superheatedsteam wrote: Sorry I can’t recall exactly what the cause was but I am pretty certain it was not related to MIP mapping or texture mapping.

The only reason I thought this is because occasionally on textured models; the texture detail reduces as the camera is panned around the loco. I think the original Flying Scotsman's Tender did this in buckets. Glad I was wrong really!

Cheers again,

Tom

PS; Thanks arabiandisco, much appreciated

Im not sure if you have sorted the problem yet.
I have had the same problem with alpha.

I managed to sort it by having all the outside parts of my model that had alpha as one group.

I then in the export manager set the sub-object ID to 1, tick the 'sort this subobject' box and set the sort priority to 5.

Then export the model as normal.

I hope this solves your problem, if you have not done it already.

If you have found a different method please let me know.

Kind regards
Matthew

If you use multiple layers of alpha then you must seperate them out so MSTS can order them. Its best to have different alpha objects for each side, and for each layer - and you must give them different subobjectid's, so they can be sorted, otherwise they get merged.

Even then, for sorting to work you must centre the pivot point of each alpha layer so each layer has a different pivot point - which means MSTS can work out the order correctly.

Although grouping all the external alpha faces can work, it will only work if alpha layers inside that don't share the same pivot point - as they will appear in the same place in z-order (depth) terms, so sorting won't work correctly. Double-sided alpha faces are also not a good idea, because when you view from the other side then the sort order may be the opposite to what it should be.

Its unlikely animated alpha layers will sort correctly if its faces pass through another alpha layer - so that may be your problem. Try using trans instead, which is more efficient anyway.

47522 wrote:Im not sure if you have sorted the problem yet.
I have had the same problem with alpha.

I managed to sort it by having all the outside parts of my model that had alpha as one group.

I then in the export manager set the sub-object ID to 1, tick the 'sort this subobject' box and set the sort priority to 5.

Then export the model as normal.

Nope; you're right; I didn't manage to sort the problem. I think I have made the model a bit too complicated; but tell me what you think.

On the outermost alpha I have the locomotive frames as viewed from any outside view; faces showing out. The I have created another set of locomotive frames with the faces pointing in. They are at slightly different widths so as not to overlap one another. Within them I have the bogie, which is a non-alpha 3d object.

(Wheels)>>Outer Frames>>Inner Frames>>Bogie

I have set the alpha layers at different "Sort Sub-objects" and with different IDs. I have a list somewhere of how they are set up; but I do not have it to hand at the moment.

Does this help explain it at all; am I doing it the preferred way?

Thanks very much for all the help so far; I'm very grateful!

Tom

hmmmm

I think there is a know bug of GMAX getting muddled when two objects are two close togeather. Stupid i know but try moving inerframes away from the outerframe a couple of GMAX inches.

Another thing to do is try having iner and outer frames as one object.
Thats what i have done for my 4 wheel wagons.
I just built plane and applied the texture to both sides, set is as BlendATEXdiff and trans in the materials editor.

I made sure the object was seperate from the main.
E.g
Main
Wheels11
Wheels12
Alpha - Set the subobjects and sub ID values for this object only.

It works for me

I knocked up a quick tester model using the method explained above and i have no problems.

You have unearthed a strange one!

Regards
Matt

Hello Chaps, apologies for bumping a year old thread- but it saves making a new one!

After a break from MSTS I had a play around with the engine and got the bug sorted. A combination of the bug Matt (47522) pointed out with close lying parts, and alpha layering problems. However, I think I have cracked it, and here is the result:



I have added some animated coal; sorted a bug with the tender wheels and got the driving wheels to run at something like the speed on the rails - so no skid effects.

Once some handrails, cab details, crew and other miscellany have been added it should be ready to go.

Must be one of the longest WIP threads ever!

Tom

MuddleandGoesNowhere wrote: Must be one of the longest WIP threads ever!
Tom

Is that a challenge?




Lovely loco.

I wonder what it would look like against the very similar Aussie loco from the same builders.

No, not a challenge!

Which engine is the Australian version? It would be interesting to compare.

Anyway. Additions; Lights/ Lamps, handrails, brackets, Alpha layering, tender livery.
Probably done apart from the crew, but I'll freightanim those, and the eng file, which'll be a pain.





Tom