[REQ] Lock texture coordinates

dacad · 1 Jun 2009, 22:11

hi guys

i don't know if this question has been made already but i was wondering if it's possible to lock the texture coordinates in the faces of a mesh? What i mean is for example having a human character modeled in the basic "da vinci" position and i texture it has i want but then i want to start deforming the mesh using the rotate, move or even the ffd plugin but i don't want to each triangular face to lose it's texture position has is it (if the faces change shape the textures in that face keep the same image even if it gest deformed, streteched etc)

Is this possible? it's incredible important for texturing organic models, even basic ones. and i can't find a workable way in sketchup for this. for my last image ("future of plastic surgery") i had to redo the texture and edit the mesh of the final face model for it to work.
This is an extremly important request, because i'm running out of tricks and workarounds for this problem

David

dacad · 2 Jun 2009, 11:17

In this image you can see what i mean. If i deform a textured fece i want the limits of the texture to remain the same for the face even if it deforms, stretch, or shrink the texture. The only way for this to hapen right now is turning every single face os a mesh into a component and just using with the scale tool (that was what i did for this image).
If the original texture was projected it will remain projected if i strech the face meaning that the face point will move but the texture position won't.

Hope i'm making myself clear enough...

Gaieus · 2 Jun 2009, 12:27

Yes, definitely the case is that in SU you don't fix the texture to a particular face (series of faces > surface) but to a certain, hidden co-ordinate system let it be the world co-ordinates or something related to the face (group/components it is inside).

dacad · 2 Jun 2009, 13:26

Thanks for the answer Gaieus.

A ruby or a sk feature like these is very important because without it we have to texture the mesh everytime we change his form, but if this worked we just have to texture it once and make infinite poses with the mesh while keeping always the same textures position.

Just for curiosity, no one else thinks this would be usefull or need it for sketchup?

Gaieus · 2 Jun 2009, 13:30

Of course I think it would be cool.

From another point of usage imagine that I texture a cylinder with a certain, carved stone pattern and then I bend it with the new Shape bender plugin and all the textures are "stuck" to the geometry and I have a beautifully textured, ribbed arch for a Romanesque or Gothic church.

So not only "posing" could benefit from something like this.

dacad · 2 Jun 2009, 16:36

Completly agree with you Gaieus.

Because most architectural stuff i've doing is more "cubic" stuff i almost forgot how usefull that could be for more than organic models. But using shape bender, as you said, would have to make a plugin like these compatible with all other modeling plugins, like a plugin working inside other plugin...don't think this is possible or is it?
Maybe these shoulde be a sketchup 8 request instead of a ruby request...the problem is i really don't believe if it matters or not what we need for them...

Chris Fullmer · 2 Jun 2009, 17:12

I have no idea if something like this is possible in Ruby. Seems like it could be. I've never looked at textures because I rarely use them. But I do see how it would be nice if it worked the way you described in some instances.

Chris

thomthom · 2 Jun 2009, 17:26

@chris fullmer said:

I have no idea if something like this is possible in Ruby. Seems like it could be. I've never looked at textures because I rarely use them. But I do see how it would be nice if it worked the way you described in some instances.

Chris

Problem is: observers. In order for this to work you need to detect when the model changes. And that is a can of blood-thirsty angry spaceworms.

What I somewhat imagine a ruby would work: the selected face is set to "lock textures". The ruby then samples the UV coordinates from each vertex (or selected points required). When the geometry changes, the ruby would then reapply the texture co-ordinates.
Given the headache I've had with observers and UV mapping I'm not sure if I'd touch this with a 10' stick. ...at least not for now...

Possible if it'd be acceptable to have a manual function to readjust the textures; might make things easier.

Chris Fullmer · 2 Jun 2009, 17:31

That idea of taking all the UV's and then re-applying them - is that fairly stable? I could incorporate it into shape bender, for eaxmple. So it wouldn't fix the problem outside of shape bender, but at least shape bender would be able to do it. AND I wouldn't have to touch any model observers.

Chris

thomthom · 2 Jun 2009, 17:47

When you set textures in SU you take a set of 3D points and specify some co-ordiates on the texture that should relate to them.

ie.
point1 -> 0.0, 0.0
point2 -> 0.5, 0.0
point3 -> 0.5, 0.5

If point 1-3 was points in a rectangle face, then that would map the texture to tile half across the face.

So, what I imagine, is that applying the same UV co-ordinates to the same points when the points move, should make the texture 'lock'.

However, your Bender widget subdivides the mesh. So you'd have to sample the UV mapping after you subdivide, but before you apply the transformations.

Chris Fullmer · 2 Jun 2009, 17:53

Interesting, thats something I'll look into the next release of shape bender.

Chris

Gaieus · 2 Jun 2009, 19:10

I'm listening guys, I'm listening...

(BTW Thom; this is one aspect I mentioned before)

dacad · 3 Jun 2009, 09:46

Thanks for the explanation thomthom and Chris Fullmer.

I was hoping it would be possible but that's too bad.... Even if it were updated manually as thom said it would still be great because i think most people would just want the textured model for the final image and not while modeling, posing or whatever, it wouldn't work just for animations.

I'm starting to see ruby as a way for sketchup developers don't work to much...

thomthom · 3 Jun 2009, 10:18

I might be possible. It's just not very easy to do. At least not automatically. UV mapping is one of the areas in SU scripting that currently feel like a bit of black magic.

@unknownuser said:

I'm starting to see ruby as a way for sketchup developers don't work to much...

dacad · 3 Jun 2009, 12:11

I mean that since ruby was introduced it was at the beggining a great way to add specific functions and automatize some actions, and then turn into part of sketchup develpment itself (every "new" stuff that it's presented it's a ruby plugin like DCs and sandbox, and this brings a dated engine to his knees) and the only hope to solve bugs and limitations of the software (we need a plugin to work as follow me was supost to, or just to draw a basic curve shape...) without google having to do nothing (the users work for advance features and solving bugs in the tools instead of the developers).

Keep in mind that we don't have any new modeling tool, animation tool or mapping/texture tool since follow me and sandbox in sketchup 4-5...but i believe that this develpment path was more a marketing decision then a development one, but still a (very) bad marketing decision

dacad · 3 Jun 2009, 12:19

But back to topic, maybe the best way for this need is to export the mesh to other 3d package texture it there and import it again to set up the final scene, but the big problem here is that importers have big problems with keeping the textures in place with uvwarping or big meshs...But is there any better way to do this??

dacad · 3 Jun 2009, 12:44

thanks thomthom.
That's what i suspected. with so many software i use to each task, i'm starting to mix up shortcuts keys lolol.

thomthom · 3 Jun 2009, 12:50

A different application might be the way to go at the moment. SU isn't very ideal for rigging. And I'm a believer of using the right tool for the right job. I think that SU might not be the right tool for this.

Whaat · 3 Jun 2009, 14:58

Here are some methods to load and save UV sets. If someone wants to use them to create a 'lock texture' plugin, that's fine with me.

def store_uvs(ents,uvset)

face=0
case uvset
	when 0
		key="uv0"
	when 1
		key="uv1"
	when 2
		key="uv2"
	when 3
		key="uv3"
end

Sketchup.active_model.start_operation "Save UV set"

for e in ents
	
	if (e.valid?) and (e.class==Sketchup;;Face)
		
		polymesh=e.mesh 5
		uvs=polymesh.uvs 5
		for i in (0..uvs.length-1)
			uvs[i]=uvs[i].to_a  #converts the Point 3D objects to arrays so they won't be transformed
		end
		e.set_attribute 'uvs',key,uvs
	
	face=face+1
	Sketchup.set_status_text("Stored uvs for #{face} faces.")
	end
		
end

UI.messagebox "UVs saved for #{face} faces."

Sketchup.active_model.commit_operation

end #function

###################position a texture on a material from a stored UV set
def position_map(entities,set)

face=0
failed=0
return if set=="SU"  
key="uv"+set.to_s
p "positioning map"
p entities
for e in entities
	p e
	if (e.valid?) and (e.class==Sketchup;;Face)
		
		uvs=e.get_attribute 'uvs',key    #gets the stored array of uv coordinates for this face for the given uv set
		p uvs
		if uvs
			pos=[]
			polymesh=e.mesh 5   #get a polygon mesh representation of the face
			polygons=polymesh.polygons  
			poly_index=0
			begin
				for p in polygons[poly_index]
					point=polymesh.point_at(p.abs)
					if point
						pos.push(point) 
						pos.push(uvs[p.abs-1])
					end
				end

				e.position_material e.material, pos, true
				face=face+1
				Sketchup.set_status_text("Loaded uvs for #{face} faces")
			rescue  #this is required because SketchUp sometimes fails to position the texture properly
				poly_index=poly_index+1
				if polygons[poly_index]
					pos=[]
					retry  #try to postion texture again using next polygon in the face
				else
					failed=failed+1
				end
			end
	
			
		end
	end
end

if failed>0
	stext="Unable to load
	UVs for #{failed} faces.  Loaded UVs for #{face} faces."
else
	stext="Loaded UVs for #{face} faces."
end

#UI.messagebox (stext)


end  #end position map

dacad · 3 Jun 2009, 17:41

WOW, thanks Whaat. Has always you're great!:)
My knowledge in ruby is very limited so can anyone help with this? (or change the name of this topic to "[Request]Lock texture coordinates")
Thanks in advance