Sketch-based interaction and modeling: where do we stand?

Sketching is a natural and intuitive communication tool used for expressing concepts or ideas which are difficult to communicate through text or speech alone. Sketching is therefore used for a variety of purposes, from the expression of ideas on two-dimensional (2D) physical media, to object creation, manipulation, or deformation in three-dimensional (3D) immersive environments. This variety in sketching activities brings about a range of technologies which, while having similar scope, namely that of recording and interpreting the sketch gesture to effect some interaction, adopt different interpretation approaches according to the environment in which the sketch is drawn. In fields such as product design, sketches are drawn at various stages of the design process, and therefore, designers would benefit from sketch interpretation technologies which support these differing interactions. However, research typically focuses on one aspect of sketch interpretation and modeling such that literature on available technologies is fragmented and dispersed. In this paper, we bring together the relevant literature describing technologies which can support the product design industry, namely technologies which support the interpretation of sketches drawn on 2D media, sketch-based search interactions, as well as sketch gestures drawn in 3D media. This paper, therefore, gives a holistic view of the algorithmic support that can be provided in the design process. In so doing, we highlight the research gaps and future research directions required to provide full sketch-based interaction support

Roman impact on the landscape near castellum Fectio, The Netherlands

Castellum Fectio was one of the largest fortifications along the Limes, the northern border of the Roman Empire. The castellum, situated 5 km southeast of Utrecht, the Netherlands, was occupied from around the start of our Era to ca. A.D. 260. It was situated along a river bend of the Rhine that was cut off from the main stream during the occupation of the Roman fort. A 6 m long sediment sequence was recovered from the infill of the residual channel and pieces of Roman wall plaster, glume bases of Triticum spelta and radiocarbon dates indicate that the sediments were deposited during the period of Roman occupation. The combined palaeoecological analyses— palynological, macrobotanical, entomological and geochemical— allow a detailed reconstruction of changing environmental conditions as a consequence of the Roman occupation. The pollen record reveals a dramatic decrease in arboreal pollen, suggesting that the Romans were involved in large-scale deforestation, transforming semiopen parkland to a landscape of meadows and agricultural fields. Non-pollen palynomorphs, botanical macrofossils and insect remains support this conclusion. The recorded mycoflora shows a shift from assemblages characterised by the tree pathogen Kretzschmaria deusta to assemblages dominated by spores of fungi associated with herbaceous plants, concurrent with the decrease in arboreal pollen. The presence of masticated bran fragments of cereals, clover remains, eggs of intestinal parasites and entomological and geochemical data in the upper part of the sequence indicates that these sediments largely consist of faeces that were dumped into the former channel. Surprisingly, seeds of salt tolerant species are encountered in the sediments of this inland site, which was situated outside the influence of the sea. Horses may have brought these seeds to Fectio in their intestinal tracts after grazing in coastal meadows