Sketchup Vertex Painting Problems

Hey all,

So I ran into this problem using Sketchup when adding colors to a model via "Vertex Painting", which is "simple colors applied to faces or corners of your model" (Thanks mkroeker!).
Naturally, adding the colors went okay in Sketchup, but when I uploaded the .dae file of my model onto Shapeways, the colors of my model are all distorted. (See attached pics)




And this is what it looks like on the product page itself:



And of course here is the model in Sketchup:




I was hoping to know what exactly the problem(s) I am having and how I can fix it. Thank you!

Make sure that the orientation of the faces (face normals) is correct (all pointing outward) - your model looks like about half of the body panels were bolted on with the undercoat (back side of triangle) showing instead of the paint job. If that alone does not fix all problem areas, look for overlapping faces or small holes/seams in your model that shapeways' site software may be trying hard to correct for you.

All of the faces are pointing outwards when I checked. There are no holes/seams in my model. Everything is essentially one watertight vehicle-shaped box. Also there are no overlapping faces that I can tell. I used a Cleanup plugin just now on the model and uploaded the new .dae file here but I'm still getting the same problems as before.

Strange. Try checking your file in meshlab, or export your geometry to STL and load that into netfabb studio basic (which as far as I know does not support DAE directly) to see what that thinks of it.

In Netfabb there are no errors present. This is what I currently see in Netfabb after I did the standard analysis:





I'm wondering if this is just with me or is it plaguing other Sketchup users.

I am out of my depth here unfortunately. As a (hopefully temporary) workaround you could try redoing your vertex painting in meshlab (Edit->Z-painting).

I would check again in Sketchup. It looks as though you have faces on top of faces.
Check to see the hidden geometry. 'View - Hidden Geometry.and Guides'. If there are any dotted lines or extra lines on flat surfaces they need to be deleted. If you delete a line and a face disappears just 'Undo' that last delete. Then check again in Netfabb. Open as an STL, as mkroeker suggested. Click on Repair 'Red Cross' if you see any faces that appear to be striped red and blue they are faces on top of each other. One face is inside out (inverted normals).
If some of the triangles are Red you definitely have inverted normals. Back in Sketchup pick a face you know is correctly facing outward, 'right click - Orient faces' should fix them. Unless you have faces on top of faces.

I did everything specified and it is still giving me the same results. I doubled check the faces and all of them are facing outward and there are no overlapping faces. All dotted lines have been accounted for as well. Went into Netfabb and triple checked using the tests. Still the same.

Is it possibly due to the way I "painted" each of the faces? Maybe the reason why the dark gray is so prevalent is because I applied a full coat of it before the other colors?

Do you have paint applied to the outside of the group? If so, that could be a problem. I'm happy to take a look if you PM me the model.

I don't believe I have paint outside the group. I just sent a PM to you with the file.

Found the problem! There are 2 things messing with your results - a material applied to the outside of the group, and a material applied to the inside (back) faces.

To fix the first problem, simply explode and immediately re-group the object. This works well on small models like this one. For larger objects where exploding can take a looooong time, you can paint the group with the default material to remove any other materials.

To fix the second problem, open the group, select all, reverse faces, and paint them with the default material. Reverse faces again to show the correct side, and you're done!

Here's an image showing where to find the default material:


Would a short video of the process be helpful?

No video needed, I did what you said and it worked!! Thank you so much! I wouldn't be where I am without your advice.

Here it is in its final form:

Nicely done! I'm glad I could help.

This thread was immensely useful!

I ran into this problem for the first time tonight, and vaguely remembered seeing the images in this discussion.

Anyway, the inside-outside trick worked like a charm! It needs to be stickied somewhere.