Do Decals apply more precisely to Peaked Models?

[Rodney]

I had a random thought so thought I should investigate.

 

The underlying observation/conjectures:

Application (and Editing) of Decal assignment in A:M can sometimes run afoul of the inherent curvature of splines.

This is one of the reasons why it is useful to flatten a model before applying decals.

 

The question

Would it generally be better to peak all the splines in a model prior to applying a decal?

 

A follow up question

After the application of the decal presumably the would be an adjustment of the assignment of specific locations of the image decaled onto the model.

What impact (if any) should we expect to see as a result?

 

 

 

I'm in the early stage of finding out the answer for myself but some of you may already know the answer.

My initial results seem to indicate (at least with spherical application) no significant difference.

[robcat2075]

My expectation is that you should apply a decal on splines in the state they would normally be in and I'm pretty sure that's true.

Do you have a case you can show?

 

 

I have often noticed distortions in realtime display that go away in final renders.

[Rodney]

Do you have a case you can show?

 

 

A case that produces a spline with odd curvature might be to take a beveled cube such as one out of the Library and decal it with an image using the spherical application method.

The initial observation not having much to do with the application of the image itself so much as the layout of decal splines that appear via Decal>Edit.

There should be at least one decal spline that has excessive curvature.

 

Beyond that I'll see if I can put together a decent project file related to this.

 

 

[robcat2075]

 

Do you have a case you can show?

 

 

A case that produces a spline with odd curvature might be to take a beveled cube such as one out of the Library and decal it with an image using the spherical application method.

The initial observation not having much to do with the application of the image itself so much as the layout of decal splines that appear via Decal>Edit.

There should be at least one decal spline that has excessive curvature.

 

 

 

i gave it a quick try. The result is not wildly unexpected. A cube is a difficult target for Spherical mapping.

 

When you have time describe me more about what you are seeing that is odd.

 

[Guest]

I don't think turning all flattened splines to mag = 0 would necessarily improve the accuracy of the decal and I'll back that opinion up with the following:

 

When I was decaling the model of my farmer's coveralls I split it into front and rear sections for flattening with the vertical break at the side seams. I wanted those seams to be as even and parallel as possible. To minimize spline stretching during the flattening process, I rotated each cp individually using the neighboring cp as the pivot (left image). I still got unacceptable distortions at the edges where the unseen splines warped back to the unflattened rear section. In retrospect, I probably should have included the next neighboring rear cp in the flattened front and then not decaled those rear patches. Instead I was able to compensate for the distortion by increasing the flattened magnitude of each edge spline to 250 which gave my useable results (right image).

So I'm guessing the spline magnitudes that yields the most accurate decal depends on your flattening choices.

[robcat2075]

In retrospect, I probably should have included the next neighboring rear cp in the flattened front and then not decaled those rear patches.

Yes, that would be essential when using "flatten"

 

My preference, when painting decals, is to use cylindrical mapping which allows my to get good UVs with just one seam instead of two.

 

However, if you are using decals from a photo, as for your jeans that may not be an option.

[Rodney]

That's an excellent example Rodger. Thanks!

 

My preference, when painting decals, is to use cylindrical mapping

 

 

 

I've been leaning toward that too.