Haven’t talked about the progress with the Nutrition project in a while. The experience is now in full production mode and on the research side the prep for the study is well under way. As a part of the production work I’ve started tackling issues involving developing a stronger sense of realism to the experience, particularly in the scale of the food models. As we want things to translate from the VR experience to the real world, we need to enforce a strong sense of proper scale to the food items to match their caloric and weight value. As scale is a relative concept, this means we have to ensure the entire scene is of a realistic scale.
To this end, I’ve had to take into consideration the units used in both Maya (the modeling tool) and Unity (the game engine) and properly translate some real world measurements between each. Thankfully, that’s why rulers exist. With the help of the Nutrition experts we’re working with, we purchased some real dietitian food models used in similar research/interventions to what we’re attempting in the experience. These models were then photographed from the top, bottom and front alongside a real 1 foot ruler. In Maya, these orthographic photos were brought in as image planes in their corresponding camera angles and lined up. The ruler in the top image was the cleanest point of reference. By making a cube with a similar ratio to the ruler and setting it to exactly 1 Maya unit in length, then scaling the image from the top perspective up or down till the ruler in it matches the cube’s length, we effectively translate the 1 real world foot to 1 Maya unit setting that unit as feet. After that it’s much easier to scale the other orthographics to properly match up with length and width of the food model in the top photo. With these orthographic photos all lined up and scaled properly, it is just left to straight modeling. Once the model is made, it’s a simple thing in Unity to set the model import setting to match the Maya unit to the Unity unit therefore the scale of the food in the Unity scene at proper scale is set to 1. The slideshow below demonstrates this process with the carrot model we got. Due to the way carrots are, I opted to model 3 of the unique shapes within the pile and then set up a script to spawn in as many carrots as needed (and even some that may be a LITTLE excessive).
That’s all just for the food modeling. As I said, scale is something relative so to make sure the food remained a proper size the room had to be also realistically scaled. In this case, I couldn’t go and take orthos of an entire room. Instead, I used the handy ruler I set up in the food modeling process and began to use it for all further modeling of furniture using realistic furniture dimensions. That meant doing a lot of stuff like looking up standard office dimensions, typical door frame dimensions, average seat height, etc. While it took a bit more time than usual freehand modeling, the final result was a small 10′ by 15′ office space with a 9′ ceiling.
The modeling process for the project is reaching about it’s end at this point and I’ve begun moving in to the heavier coding and layout of the experience to match the segments described in our study plan. This includes the addition of a virtual dietitian to guide the users through the experience in one version as a baseline to compare the more independent, interactive exploration to. Things will hopefully continue smoothly till we’re able to fully test the whole package and start preparing for the full pilot study.
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