Adding Texture with Pepakura 3 Problem

[StormDragon]

Software: Pepakura designer 3.0.7a
Model: a Mushroom with 2 components (cap and base) exported from Sketchup as .kmz (Google earth 4)

So, according to several discussions I've seen, it should be easy to apply a new skin to a model in pepakura.

I'm finding it anything but.

I was originally trying to use a complex model I designed, and failed, so I tried the mushroom you'll see in the picture attached.

The cap and base were both left uncolored, untextured. I unfolded the model, then clicked "Settings >> Texture Settings" I selected the "FrontColorNoCulling" option, specified my texture, and ended up with the picture you see.

Then I went back to my source drawing, selected the cap, and colored it red. When I returned to Pepakura I was able to select "Material0" now, and replaced it with the same texture.

Now the bottom is still plain and the TOP is goofy. When I zoom in there are MILLIONS of those little things on the cap.

So, HOW do I scale up that texture to make it appear the way I want it to on my drawing? (green cap, with 4 large white spots?)

I googled a tutorial, and it worked fine for them, but I'm missing something.

[StormDragon]

Okay, got a little closer.

Instead of a solid color for the cap, I used a texture, then scaled the texture up a bit. When I loaded the new texture, it scaled up, so no little bitty dots. Now to figure out how to get just FOUR dots.

[StormDragon]

okay, so I applied the red texture to the mushroom in Sketchup using a technique where you "Project" a texture from a flat surface to a curved, or angled surface. This gave me 4 faces. I used 4 different sized textures in the source model, and exported the .kmz. (from Google Sketchup, I should add)

Open the model in Pepakura, and I can swap the scaled skins with the green skin, and get great results. The green texture is replicated, no mater what scale the other textures were (128, 256, 512, and 1024 respectively)

So, Pepakura doesn't like to apply textures over solid colors. I guess this is because pure color has no reference data, like an image does.

[codex34]

Solid colours and textures do not hold the UV data needed to texture a model.
It is the model that contains the data needed to texture a model, so no, you can't just replace colours with textures, in pepakura or any 3D program for that matter.
Sometimes 3D programs will automatically 'map' an object you create with UV co-ordinates to make life easier for you so it may seem like you can just replace colour with textures, but in general you need to map the textures onto the model before you export it to pepakura, (in just the way you did) pepakura has no ability to do this at all.
I think the threads you read were meant for replacing textures with re-coloured versions of the same texture.
The numbers stored with the model, the UV co-ordinates, used to map textures onto the model are just X,Y co-ordinates for the image, they are stored as a unit vector (ie 0 to 1) which means it doesn't matter how small or big the texture is, the X,Y co-ordinate will be at the same relative position within the image. A U value of 0.5 will point to the half way point in the X axis no mater what size image you have.

Bit of a warning for pepakura, it has a horrible image resize function which will always mess your textures up if your not careful, it's something like a cross between a bicubic sample and gaussian blur.
In setting, other setting, advance, there is a checkbox labeled "smooth texture image", if it is checked it will attempt to resize any image below 512x512 to 512x512, my suggestion is to ALWAYS uncheck this option as the image it produces is REALLY bad (a monkey with a turd could do a better job)
It also only likes 2ⁿx2ⁿ size images, so if you use an image say 345x456 it will attempt to resize it with its internal function, you need to resize your images with a better program if they are not a 2ⁿx2ⁿ size.
BTW, it normally takes more time to texture a model than it does to make the model, it's not difficult, just time consuming, especially when you need to make the texture from scratch.

[ThunderChild]

Codex hit the nail on the head. Your texture image needs to be square and you need to set the UV coordinates on the model itself. Best way forward is to try searching for tutorials on "UV Mapping" for your 3d software...

[Lex]

Baseline is, Pepakura is not a 3D editing software, which includes UV mapping. There are one thousand and one ways to project a texture onto a model and Pepakura only trusts what other 3D software tells it to do... It doesn't know how to do this by itself

[StormDragon]

Wow, thanks for all the background information guys. Although I've been making paper models for a while now, I haven't actually designed all that many. (A grand total of 11, in fact)

Something else I noticed after I posted in here originally, those thousands of tiny dots showed up again during posts 2 and 3. Took me a while to figure it out. I'm using Sketchup as my 3d software (free and not too complex... cheap and easy, that's me). When I projected my image onto the face I wanted to model, it looked great. Import to Pepakura, nightmare, with thousands of those little dots.

After about 15 minutes of head banging into keyboard, I found the projected image on the INSIDE FACE of my model. I cleared it out, exported to Pepakura, and voila, little guys gone. Had to "reverse faces" to figure out what was going on. I think I did this in pepakura, but not really sure.

Sorry if I posted a bit of a rambling thread, but I didn't see another thread in here about anything like this, so figured I might get some help, and my eventual solution may always be helpful to someone down the road.

Which will probably be me, given the fact I have a brain like a steel collander.