Decal Challenges - Continuation

[pixmite]

This is a continuation of a topic started here:

 

http://www.hash.com/forums/index.php?showtopic=18978

 

Below is an Image of my model to which I applied a bump decal with straight lines which render with jags. The decal is un-edited in the UV editor. No points were dragged or the model flattened.

 

Any ideas on how to fix this? or a better approach to straight lines?

 

Pixmite

 

P.S. Vernon - I think you were right about the optical illusion. I rendered it from another couple of angles and it looked correct. I was late, what can I say.

[ddustin]

This is a continuation of a topic started here:

 

http://www.hash.com/forums/index.php?showtopic=18978

 

Below is an Image of my model to which I applied a bump decal with straight lines which render with jags. The decal is un-edited in the UV editor. No points were dragged or the model flattened.

 

Any ideas on how to fix this? or a better approach to straight lines?

 

Pixmite

 

P.S. Vernon - I think you were right about the optical illusion. I rendered it from another couple of angles and it looked correct. I was late, what can I say.

 

I agree this will be tough to use a bump map on.

More that likely I would end up modeling the creases, you'll spend as much time messing with the maps to get it right as it would take to just add the splines.

 

Just my 2 cents or pence or dinaro or rubles or won or yen or..............

[Eric2575]

Pix:

 

Stuff like this really intrigues me. I know you could just model more splines, but for my part, I'd like to know why this happens and what can be done to avoid in the future. I've applied decals to a tire and did pretty much what you did - applied from the front and then applied the decal to the inside of the back of the tire. I don't remember having the trouble you did though. I'm sure you're not moving the model as you do this, but just make shure. If you'd like, send me the file and I'll try to see what I can do with it. You can edit the file to include just the tail section if you like, just so I have the decals and the problem section of your model. Pm me if you want me to try.

 

Eric

[zandoriastudios]

What about using a cylindrical map for the bump detail on the fusalage?

[R Reynolds]

Would you please post a shaded wire frame of the same area of the model? I've had similar problems when decals are applied to hooks.

 

For the bump maps that are the wrong polarity on the right side, you flip those bumps by opening up that decal image and setting it's bump percentage to a negative number.

 

or a better approach to straight lines?

Decals tend to follow the curve of splines (which is probably great for applying makeup to a face but for painting racing stripes on car hoods, not so much). The only sure solution I've found is to increase patch resolution (maybe 2 or 3 times) in the region where you want straight and orthogonal decals and then get absolutely obsessive over making sure all splines are as straight and even as possible. In one case I had to draw a pre-distorted decal (using an iterative process) which the decaling alogorithm then took out on application. Ah the joys of building machines with an app optimized to animate characters.

[ericsh6]

I think it is a bug that needs to be reported. I use version 12.0 and I use tga with alpha channel created in Gimp to decal onto mountain terrains to create mountain wear and get the same thing except that I see swirls where there should be straight wear lines. I think bump maps are a good way to make creases and that it is worth getting this fixed in A:M. I wonder if it is Gimp though?

[pixmite]

Below is the shaded wire frame version. Some of the area in question has a 5-point patch or a hook but not all of the problem area????

 

I'd prefer not to have to model all of the panel lines if possible. A cylindrical map might work for all the vertical lines, but I'll probably need another decal for the horizontal ones. I'll give it a try and report back to this thread.

 

As for setting the bump % to -100, this is done at the decal level, to fix my problem it would have to be done at the Stamp level.

 

Lastly, I would tend to agree that this is a bug, if a color decal doesn't have any problems why should a bump map?

 

Pixmite

[Scottj3d]

I hope this will help. I have been making some space ships for a friend and ran into a similar prob. My solution was to create the lines on a transparent layer then once you have them worked out how you want them make a copy of that layer on top of the original then apply a gaussian (spellcheck that) blur to the underlying duplicate. My prob I assumed was antialiasing but it this technique made much smoother lines and I had no prob lining them up from left to right. I did also flatten the fuselage in a pose before applying the decals. Here's the result. Sorry I cant show the whole ship but I promised not to let the cat out of the bag.

[R Reynolds]

Sorry, I'm stumped.

 

I quickly built a similarly shaped "fuselage" and decaled vertical bump stripes on it in the manner you described and they produced the expected results without any of the strange discontinuities you're getting.

 

My only suggestion is to make a test copy of just the fuselage as a new model and strip out all decals and materials. Then starting with a new project and a clean model, apply only the bumps maps and see if you can reproduce the problem.

[heyvern]

BRAINSTORM!!

 

I may be completely wrong... but this happened to me a couple of times in the past and drove me nuts till I figured out my mistake...

 

Make sure that you don't have any "overlapping" decals.

 

The mistake I made was inadvertently decaling one side over another decal. It looked like my decal images weren't "lined up" but actually I was seeing a few errant patches that got stamped with the wrong... stamp.

 

Just a thought... probably not the same problem for you... worth a look. Rodger's suggestion would find this out.

 

Vernon "!" Zehr

[arkaos]

Pix,

 

It almost looks like the side of the fuselage is distorted in accordance with the color of the texturing behind the numbers. Check to make sure you don't have a stamp whose parent image is set to "bump", "normal" or "displacement" mapping. That is what it kind of looks like if you compare the render picture with the shaded/wire picture.

[pixmite]

Fellow AMers:

 

Thanks for all your suggestions; they were a great help to discover what the underlining (no pun intended) problem was.

 

I did some further experimenting last night. First, I did try the bump decal set for cylindrical mapping, which didn’t work.

 

Next I tried a fresh decal that I quickly created and it worked great! So I said to myself… Self what beep beep is going on here???

 

 

Well….

 

When I originally stated that I didn’t edit the points in the UV editor after a stamped the decal wasn’t completely accurate. Following the Zandoria Decal Tutorial, I was maximizing the real estate of my blank decal by selecting the entire CP group of the two fuselage stamps together, scaled them up and moved them to a more strategic location on the decal in the UV editor.

 

While performing my quick test above, I neither moved nor scaled the complete stamps. Upon further experimenting moving the stamps where found to not cause the problem, but scaling the Stamps did.

 

So the moral of the story is….

 

DO NOT SCALE COMPLICATED COMPOUND CURVE SPLINE GEOMETRY IN THE UV EDITOR!

 

Lastly, if you look closely at the camouflage decal of the first image posted above you can see that it affected it as well. I also up-scaled the CPs of this Stamp in the UV editor when I created it.

 

Does this sound like a bug or just me not understand the limitations of the UV editor?

 

Once again, thanks everyone for your suggestions, you we all were a great help!

 

Pixmite

 

 

[pixmite]

All here's the TA-DA pic. Its a new Bump decal where no stamps were scaled in the UV editor. Note that you can still see the jags on the color decal, I haven't created a non-scaled stamp version of that one yet.

 

Pixmite

[heyvern]

Well...

 

I wouldn't call it an "issue" specifically.

 

Keep in mind the UV editor is really just a "flattened" version of the actual mesh. So, yes... if you scale and move a bunch of stuff in the UV editor, the splines and CP bias could go wonky on you.

 

If you have ever worked in a flattened pose or action of a face or any type of model, and have stuff "hidden" so you can just flatten parts of it...

 

... and you unhide the stuff that hasn't been touched... you can see why those distorted patches happen.

 

-------------

As I have been reading this thread... a vague memory comes back... I may have encountered this before... it just seems so familiar to me... (imagine a wavy distortion over my face as I look up to the right thoughtfully).

 

Anyway... I am very glad you found a solution... even if a partial solution.

 

Vernon "!" Zehr

[pixmite]

All here's the TA-DA pic. Its a new Bump decal where no stamps were scaled in the UV editor. Note that you can still see the jags on the color decal, I haven't created a non-scaled stamp version of that one yet.

 

Pixmite

 

If you look closely at the picture associated with the quote above, you can see that some of my panel lines that are not vertical are a bit rough. I'm pretty sure that this is due to the resolution of my panel line image not being high enough so that the anti-aliasing is visible on the model when rendered. This can also be seen around the edges of the number “18” decal.

 

Does anyone have a good rule of thumb on establishing the necessary resolution of an image applied to a decal stamp to make the anti-aliasing of the decal not noticeable when rendered?

 

Example: If my decal Stamp is 3” X 5” then the image applied to the stamp should be 12” X 15” to hide all anti-aliasing, i.e. a ratio of 3 to 1.

 

Pixmite

[heyvern]

It is more important to determine the size of the entire "final image" and how close the camera gets to the decal image.

 

In the final render size... make a "guesstimate" on how "big" the decal image is in the rendered image and use that for calculating the size you need.

 

These samples you have done are not how the final image would look, scale wise. It is the final composition of either the animation or the still image that would determine how much resolution the decal needs. If the camera zooms in real close... you would need a really big hi-res image.

 

This is actually a good thing because what you can do is not worry about it for now. When you get to the point that you want your final render... then make modifications to the decal image... upping the resolution.

 

AM will update it and your done.

 

I actually work "low-res" on some decals until the very end. Saves time and speeds things up while I am working on the composition. As long as the "bigger" image is exactly the same proportions it will just update in AM.

 

Vernon "!" Zehr