Blender mesh models

[Coldpaws]

I am using blender as my modeling program when ever i use catmull-clark mode and i put a deck on the boat or floor for like a engine room etc the hull just dives inwards and i do not know how to stop it from doing that

[Drongle McMahon]

Not quite sue what you mean. Possibly: Try creasing the edges you want to keep intact (picture; 0.5 in the middle, 1.0 top and bottom), using Mesh->Edges->Edge crease (or shift-E).

[Coldpaws]

here is my hull before the dive in

[Coldpaws]

hull after the dive in with a floor

[hibit Spad]

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Coldpaws wrote:

I am using blender as my modeling program when ever I use catmull-clark mode and I put a deck on the boat or floor for like a engine room etc the hull just dives inwards and I do not know how to stop it from doing that

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After looking at you photos,  you got one messed up problem.

 

As I recall Catmull-Clark is a smoothing routine  (I don't have access to my blender machine just right now.  That means it does not like sharp edges.  Every where it finds one it will fight against it if possible.

 

From you pic it looks like you have made the deck part of the hull mesh?

If so try making it a separate object.    From my own boat making experience I think you will find it imports easier.

 

 

 

 

[Aquila Kytori]

Hi

If your model is for uploading to SL you should always try to avoid using any Subdivision Subsurf especially for a full size boat like the one you are creating because when rezzed inworld it will have a LI of anywhere between 200 and ........well 1000's.

Perhaps you intend to retop? But if not I suggest you do a test upload on the beta test grid as your model is now.

The easiest way to get a relatively low poly smooth boat hull shape is to do a Google search for hull plans of the type of boat you are modeling and load that as a background image into blender. The plans should contain numbered cross sections of the hull. Trace out each half cross section with some vertices and then position them according to the side view plan and then fill in the faces.

Add a Mirror modifier and set it to smooth shading .

One I did earlier :

 

 

[Coldpaws]

am trying to build a cape cod hull, i uploaded a test hull already and only side is visible but when i rotate to the other side the other side becomes visible

[Aquila Kytori]

Then it sounds like you have the normals of the mesh faces facing the wrong way. They will need to be recalculated or Flipped in Blender.

See this thread :

http://community.secondlife.com/t5/Mesh/Confused-Uploader/m-p/1887481#M19270

Its a good idea to work with Back Face Culling enabled in Blender because then you will see if your model has any normals facing the wrong way as you are modeling.

[Coldpaws]

i found some plans am i able to like move the certian parts of the hull to give it a unique design?

[Aquila Kytori]

Of course lol . Tweaking the model is a very impotent part of getting just right .

There are plenty of video tutorials that use background images (plans or photos) as there stating point. One showing how to model an airplane is just as relevant as one modeling  a boat. They both use the same process.

Just keep in mind that often you will find tutorials where the end result is a high quality rendered image (high poly, liberal use of Subdivision subsurf modifiers lol ) whereas if you are modeling to upload into SL it has to be low poly so just skip the part where it uses subsurf.

[Coldpaws]

all i did with the model you seen was start with a cube was scale mirror modify then loop cuts etc

[Coldpaws]

cant fidn the backface culling mode....

[Gaia Clary]

Backface culling:

 

• In the 3D View open the properties sidebar (press 'n')
• locate the Shading panel
• There you can enable/disable backface culling

[Gaia Clary]

Scale and Mirror are good candidates for getting flipped normals

 

• Open the Properties sidebar (press 'n')
• locate the Mesh display panel
• There you can enable the display of Face Normals

Now you can see if your normals are correct. normals should all point "outward". Only the side of a face from where the normal sticks out can later be seen in SL.

 

• Mesh -> Normals -> ...

There you you find funtions for recalculate inside, outside, or flip normals.

[Coldpaws]

now am trying to find a way to put a image in to try that way too

[Gaia Clary]

May i propose you first try to walk before you try to fly ? Take some basic course for blender before you try to create a model with it ?

This is not bad as starter:

http://cgcookie.com/blender/cgc-courses/blender-basics-introduction-for-beginners/

[Aquila Kytori]

3D Editor > at the bottom of the Properties panel (N) in the   > Background Images.

There you can load up a background image , set which views it will be displayed in,  scale it up or down , reposition it etc. Note you have to be in Orthographic view to see the background image . Num pad 5 toggles between Orthographic and perspective view.

http://community.secondlife.com/t5/Mesh/blender-blueprint-problem/m-p/1659499#M16695

 

Edited after seeing Gaia's post :

Of course you should be be able to swim before going out in a Cape Cod fishing boat . For a The Perfect Storm a life jacket is not enough. So take some lessons 

[Drongle McMahon]

Ah yes. The pinching is the result of adding the floor to a mesh with only one side. The edges along the joint of floor and walls have three faces joining at the same edge. This is one of those "non-manifold" structures that you have to avoid. (You can detect them with Select->Non Manifold). The subsurface algorithm can't deal properly with this structure. If you make the hull with a proper inside (eg: Mesh->Faces->Solidify). You need this to see the inside surfaces anyway. Then remove those parts that you aren't going to see and close the hole with the floor. If you need to have a visible inside below the floor too, then you make that as a separate disconnected sirface. The picture shows these two stages in transverse section, along with your model on the left. These models will not show the same artefact if you add a subsurf modifier, but you will still get other problems to solve with creasing etc.  Better to avoid subsurf altogether, As aquila said, you can make a much more polygon-efficient model without it. If you do use subsurf, you can remove a lot of the redundant edge loops with Dissolve.

[Coldpaws]

so i can use my model still?

[Drongle McMahon]

I don't see why not. In fact there is an even simpler way to add the floor. Just make it completely unattached to the hull, so that its edges are hidden within the double walls of the hull. Of course, the double walls have to be thick enough for that. As far as the subsurf is concerned, there's nothing to stop you using it, as long as no material has more than 21844 triangles (see here), but it will give you needlessly high poly counts, which means high LI and high load on the gpu of anyone looking at it. If you use it and then remove redundant edge loops, it can be quite useful. However, you are advised to use smooth shading instead as far as you can (with the edge split modifier if you need some sharp edges). Direct views of the surfaces will be fine. It's along the edges of the silhouette that smooth shading doesn't help, and that determines how much subdivision you need.

[Coldpaws]

heres a view of my hull in SL beta server

[Coldpaws]

sorry for so many questions but how do i make the boat engine? do i do it seperatly then put it in place ingame? or make it into the current model?

[Aquila Kytori]

hi again,

Yes it would be better to model the engine as a separate Object and upload it separately. Doing it this way will probably make for a lower overall LI (Land Impact cost).

[Drongle McMahon]

Your picture shows some strange shading aroud the top. I think you can mend that by making the top edge sharp. To do that, select the edges around the top and do Mesh->Edges->Mark sharp. Then add the Edge Split modifier, uncheck the Edge Angle box and check the Sharp Edges box. This gives you precise control over which edges are treated as sharp and which are shaded across smoothly. Note that the vertices along the sharp edges are duplicated when you upload (with apply modifiers) which can increase the LI if there are very many. Also, if you combine with a subsurf modifier, the edge split must come after it. Otherwise the split edges will be peeled back from the edges.

[Coldpaws]

the bow has a flare to it it goes up flares out and mvoe up again

 

is it best to make the wheel house, sleeping area etc all seperate or all one piece?