MDU 115 – Asset Modelling Workflow

AKA, Adventures in modelling a hot air balloon.

(aka, Kate gets too far in before realising that UV mapping a round object is not going to be fun)

To begin with I decided to go with a vehicle from the list of assets to model, figuring that a hot air balloon would be a pretty good mix of easy and challenging. After googling around a bit I decided to go with a vintage style balloon.



(some reference images I found, and a page of notes I took before beginning modelling)

The actual modelling stage of the balloon was pretty simple – other than a brief problem where a number of vertices became misaligned on the basket (which led to an attempt to remake it before I realised it was actually quite a simple fix)

I decided to make good use of alphas when it came to the ropes – this is extensively used in many game models, and I’ve had experience texturing with them before so I was on pretty solid ground.

(That experience with messing around with game models and their alphas was useful when fixing a normals problem with the alpha – I remembered from editing hair meshes that to get the textures to show up on both sides of an alpha, you can duplicate the layer, shrink it by a tiny amount and then reverse the faces. Weird vanishing alpha problem fixed!)

On the other hand, by the time I reached the UV unwrapping stage, I was wishing I’d gone with something simpler. Two large round objects did not make for a very enjoyable time. They’re still not perfect – but I think I went with the option that was the easiest to texture, while maintaining as little texture stretching as possible.

2015-05-07 14_32_45-hot air balloon mapping 09.max - Autodesk 3ds Max  2015  - Student Version

(The ropes UV map complete)

2015-05-07 14_33_00-hot air balloon mapping 09.max - Autodesk 3ds Max  2015  - Student Version

(How the ropes layer was mapped – note the stretching on the lower half of the balloon, though I created the texture in such a way that it was not noticeable)

Texturing the model was probably the most enjoyable part – again I’ve textured game models before, both painted from scratch and cobbled together from various textures, both techniques I used on the the model. The basket has the most outside texturing – most notably the wood and the wicker textures, while both the balloon and the rope were created entirely by me.

2015-05-07 15_39_53-Hot Air Balloon - fully mapped01.max - Autodesk 3ds Max  2015  - Student Version

(an early test of the texture – just laying down some flat colours, and lining up shapes – I do like how it displays in the viewport, one day I would like to find out just how to render like that)

basket and supports texture basket and supports texture_NRM

(a work in progress shot of the basket and support ring, as well as the normal map I generated using crazy bump. I also created an ambient occlusion map for the final render of the basket using 3Ds Max’s render to texture feature)

hab_ropes_texture hab_balloon_texture

(Ropes and Balloon texture)


The first of the ‘final’ renders – this comes after several hours of nerve wracking attempting to try and get lights to show up normally and not leave strange streaks of black all over the balloon – I finally just gave up and stuck a sky light right over the top of the balloon. Rendered with mental ray.

sky_skydome texture

I decided after rendering it out that it looked a little dull – the grey was great and all for showing the details, but it wasn’t really doing it for me – so I took the idea of the skydome from the chest assessment and added one to the scene. It’s just a half sphere with a sunrise sky texture badly stuffed onto a rectangular uv map (total time: ten minutes – pay no attention to the ugly seam in the middle please :P)


I’d say the result was worth it right?

(says the person rendering out a 250 frame spin with a total render time of ~7 hours! I’m three in, with four more hours to go, if the prediction is to be believed!)


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